1995 Review and Extension Conference
of the Parties to the Treaty on the
Non-Proliferation of Nuclear Weapons

15 March 1995

New York, 17 April-12 May 1995


Background paper prepared by the United Nations Secretariat



I. INTRODUCTION ......................................... 1 - 3

II. MAIN DEVELOPMENTS, 1955-1989 ......................... 4 - 17


A. General Assembly ................................. 19 - 22

B. Amendment Conference ............................. 23 - 29

C. Moratorium ....................................... 30 - 36

D. Conference on Disarmament ........................ 37 - 47


1. At its second session (17-21 January 1994), the Preparatory Committee for the 1995 Review and Extension Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons invited the Secretary-General to prepare for the Committee's third session (12-16 September 1994) a short background paper on the main developments since the Fourth Review Conference (1990), within and outside the framework of the United Nations, with regard to the implementation of the tenth paragraph of the preamble of the Treaty, i.e., the achievement of a comprehensive nuclear test-ban treaty. At its third session, the Committee requested the Secretariat to amend the paper in the light of comments made in the course of the session, to update it by taking into account current events and to submit it to the Conference. The present paper is submitted in response to that request.

2. The question of nuclear-weapon test explosions represents one of the longest-standing issues on the disarmament agenda of the international community. It has been dealt with in the framework of multilateral, trilateral and bilateral negotiations since 1954, when India proposed a so-called "standstill agreement" on testing. Interest in the subject first arose as the general public became increasingly aware of the [potentially] harmful nature and effects of the fallout from atmospheric nuclear tests and as it became apparent that no region could avoid being affected by radioactive debris. The issue of the ban on nuclear-weapon tests was subsequently pursued intermittently as an element of comprehensive plans for arms control and disarmament, as a separate measure interlinked with progress in other disarmament areas and as an arms limitation issue on its own. In each case, the question of verification has played an important role and has influenced the course and outcome of the negotiations. By 1994, three treaties regarding nuclear testing - one multilateral (see paras. 5-7) and two bilateral (see para. 9) - had been concluded. They have limited the environments for carrying out such tests, on the one hand, and placed ceilings on the size of the explosions, on the other. The declared objective of the ongoing negotiations is to achieve a comprehensive nuclear test-ban treaty.

3. It is estimated that from the beginning of the nuclear age on 16 July 1945, when the first atomic test was carried out at Alamogordo, New Mexico, United States of America, to the end of 1993, some 2,000 nuclear test explosions were conducted in the world as follows: United States, 1,051; 1/ Union of Soviet Socialist Republics, 715; 2/ United Kingdom of Great Britain and Northern Ireland, 44; 3/ France, 192; and China, 39. 4/ In addition, in 1974, India announced that it had conducted an underground explosion of a nuclear device for peaceful purposes. Of the total of all tests carried out so far, it is estimated that 579 took place in various environments prior to the signature of the Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and under Water (the Partial Test-Ban Treaty). With the conclusion of that Treaty in 1963, the three nuclear-weapon States parties ceased all their tests in the three prohibited environments. France and China, while not becoming parties to the Treaty, stopped such tests in 1975 and 1980, respectively. Since then, all the tests carried out have been confined to underground tests.


4. Formal efforts to negotiate an international agreement to end nuclear tests were initiated in the five-Power Subcommittee of the United Nations Disarmament Commission in 1955. In 1957, the General Assembly included the question as a separate item on its agenda. The issue received further prominence with the convening in October 1958 of a tripartite Conference on the Discontinuance of Nuclear Weapon Tests, composed of the Soviet Union, the United Kingdom and the United States, which focused exclusively on the issue. The Conference adjourned its work in January 1962 without being able to complete the drafting of a treaty owing to persistent disagreement on the adequacy of national means of detection as the method of verification of the test-ban treaty in all environments. During the larger part of this period (1958-1961), the three nuclear-weapon States observed a unilateral voluntary moratorium on testing. In 1961, the Ten-Nation Committee on Disarmament, meeting at Geneva, became the Eighteen-Nation Committee on Disarmament, and consideration of the test-ban issue was moved to that Committee in 1962.

5. Building on some elements of progress made in the tripartite Conference before it adjourned, the objective of the Eighteen-Nation Committee on Disarmament continued to be the achievement of a comprehensive nuclear-weapon test agreement. Various differences in positions between the negotiating parties were further narrowed down. The main remaining problem, however, concerned verification. Apart from the questions of the number and location both of the control posts and of the automatic seismic stations, and their method of operation and ownership (national or international), the main difficulty centred on the number of international on-site inspections permitted to be carried out on the territory of the nuclear-weapon States: three or seven. The solution to this question remained elusive and prompted the three nuclear-weapon States members of the Committee, i.e., the Soviet Union, the United Kingdom and the United States, to pursue an agreement with a more limited scope, in which the question of verification would not create a major problem since it could be ensured through national rather than international means. That meant leaving the underground tests outside the scope of the treaty, which, in the opinion of the Western nuclear-weapon States, required an international system of verification, including on-site inspections.

6. Agreement was reached on 5 August 1963, when the United States, the United Kingdom and the Soviet Union signed, in Moscow, the Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and under Water. They also invited all other States to join in. The Treaty entered into force on 10 October 1963; as of 31 December 1994, there were 124 parties to the Treaty.

7. The Treaty, which is of unlimited duration, affirmed in its preamble that the three original parties to the Treaty, the United States, the United Kingdom and the Soviet Union, were seeking to achieve the discontinuance of all test explosions of nuclear weapons for all time and were determined to continue negotiations to that end. That statement was reiterated five years later, in 1968, in the tenth preambular paragraph of the Treaty on the Non-Proliferation of Nuclear Weapons, which recalled the determination expressed by the parties to the Partial Test-Ban Treaty to bring the testing of nuclear weapons to an end.

8. Since the conclusion of the Partial Test-Ban Treaty, the efforts of the international community to ban nuclear-weapon tests have continued in two directions. On the one hand, appeals were made, mainly in the General Assembly, for transitional measures of restraint that would suspend testing or limit or reduce the size and number of tests pending the conclusion of a comprehensive ban. On the other hand, the nuclear-weapon States were urged to proceed expeditiously towards negotiating such a comprehensive ban.

9. As regards transitional, partial measures, after initial hesitation on the part of the nuclear-weapon States to engage in any such negotiations on the grounds that this approach would neither solve the problem of adequate verification (the Western position) nor help stop the build-up of nuclear arsenals (the Soviet position), on 3 July 1974, the United States of America and the Union of Soviet Socialist Republics concluded the Treaty on the Limitation of Underground Nuclear Weapon Tests (the Threshold Test Ban Treaty). In doing so, the two sides were motivated in part by their desire to improve their mutual relationship. The Treaty established a limit on the amount of energy that might be released by underground explosions, i.e., their explosive yield, which had been set at 150 kilotons, with effect as of 31 March 1976. Since the Treaty did not cover underground nuclear explosions for so-called peaceful purposes, which could not be distinguished from explosions for military purposes, in order to close possible loopholes, the two sides concluded on 28 May 1976 the Treaty on Underground Nuclear Explosions for Peaceful Purposes. 5/ The Treaty extended the prohibition under the Threshold Test Ban Treaty to explosions carried out by the United States and the Soviet Union at locations outside their nuclear-weapon-test sites, also with effect as of 31 March 1976. Although not a party, France has on a voluntary basis complied, as of 1975, with the limitations set by the two Treaties. 6/

10. The conclusion of the two Treaties was welcomed by the international community. However, both in the Conference on Disarmament and in the General Assembly, a number of States repeated the view that the partial approach could not replace the need for a comprehensive ban on all tests, which remained an urgent objective. Year after year, the General Assembly has continued to stress this point in its resolutions.

11. The efforts to arrive at a comprehensive ban on nuclear testing have taken place mainly in the Conference on Disarmament and its predecessors at Geneva. While the negotiations conducted in that body touched upon a number of intricate aspects of such a ban, they mostly focused on the question of verification, still perceived to be a crucial element in any such undertaking. It was not before the second half of the 1970s, however, that the considerations became fully focused on this particular aspect of such a Treaty. In 1976, the Conference on Disarmament agreed to establish an Ad Hoc Group of Scientific Experts to Consider International Cooperative Measures to Detect and Identify Seismic Events. This work has continued until the present and, on the whole, has achieved significant progress.

12. The consideration of a comprehensive test-ban treaty received some special impetus at the first special session of the General Assembly devoted to disarmament, held in 1978. In the Final Document of the session, Assembly resolution S-10/2, adopted by consensus on 30 June 1978, the Assembly stated in paragraph 51 that a treaty prohibiting nuclear-weapon tests "should be concluded urgently and the result submitted for full consideration by the multilateral negotiating body with a view to the submission of a draft treaty to the General Assembly at the earliest possible date".

13. The following year, 1979, the three nuclear-weapon States parties to the Partial Test-Ban Treaty - the Soviet Union, the United Kingdom and the United States - resumed trilateral talks on a comprehensive test-ban treaty. Their negotiations lasted until 1980 and made notable progress towards the achievement of a verifiable comprehensive agreement on the cessation of tests. A detailed report on the negotiations was presented to the multilateral negotiating body in 1980 7/ and, later that year, to the Second NPT Review Conference. Shortly afterwards, the negotiations were suspended. Nevertheless, efforts to achieve a comprehensive agreement on the cessation of tests continued within the framework of the multilateral negotiating body at Geneva. However, relations between the Western negotiating partners on the one hand and the Soviet Union on the other had meanwhile worsened considerably.

14. The deterioration in international relations as of the beginning of the 1980s led, in part, to changes in the policies of the major nuclear-weapon States on the question of a comprehensive test-ban treaty. Thus, the United States made public its view that nuclear testing was important for the security of the Western alliance, which depended on the maintenance of a reliable nuclear deterrence and that, consequently, it could consider a comprehensive test-ban treaty only as a "long-term objective" whose realization must be sought in the context of radical nuclear arms reductions, expanded confidence-building measures and, particularly, improved verification capabilities. France and the United Kingdom, in their policy pronouncements, reflected the same basic position on this issue. The non-aligned States, on the other hand, continued to maintain their long-standing view on the question of testing, namely, that a comprehensive test-ban treaty was an urgent requirement since it would make a significant contribution to ending the qualitative improvement of nuclear weapons and the development of new types of such weapons and of preventing the proliferation of nuclear weapons. This, by itself, they noted, would strengthen international peace and security of all States and would significantly advance the cause of nuclear disarmament, which the three nuclear-weapon States parties to the Treaty on the Non-Proliferation of Nuclear Weapons were under commitment to pursue in good faith. These basic positions on the question of testing, particularly the one emphasizing its urgency and the second placing it in a broader context of disarmament and international security, permeated all subsequent efforts to restart the work on such a treaty.

15. The Conference on Disarmament became seized of the matter once again in 1982, when for the first time an agreement was reached on the establishment of an Ad Hoc Committee on a Nuclear Test Ban. The mandate of the Committee was a limited one, however. It achieved no tangible results in its work because of continued disagreement over the scope of that mandate. Some measure of progress was achieved, however, in the Ad Hoc Group of Scientific Experts to Consider International Cooperative Measures to Detect and Identify Seismic Events. The Group held a number of substantive discussions and submitted periodic reports to the Conference on Disarmament. More specifically, in 1984, the Group conducted what appeared to be a successful trial data exchange test for a proposed world seismic data network (GSETT-1). Subsequently, in 1991 the Group started a full-scale data exchange test (GSETT-2) (see para. 39 below).

16. The issue continued also to figure prominently on the agenda of the United Nations General Assembly. In addition to various resolutions urging the nuclear-weapon States to intensify negotiations on a comprehensive test-ban treaty (none adopted by consensus, however), the Assembly, in 1986 and 1987, called upon the nuclear-weapon States to provide information on their nuclear explosions and requested all other States that possessed data on such events to make them available to the United Nations. Since then, the Secretary-General has submitted annual reports to the Assembly with the data received.

17. This, then, was the general background against which the Fourth NPT Review Conference was held in August 1990. The question of a comprehensive test-ban treaty was one of the main issues in the discussions at the Conference. However, the basic positions of the various political groups remained much the same, notwithstanding some progress in the consideration of the issue outside the framework of the Review Conference, most notably an agreement on a compromise mandate for the Ad Hoc Committee on a Nuclear Test Ban reached in the Conference on Disarmament earlier that year. Owing to the outstanding differences, as well as differing assessments of the state of the implementation of the Treaty's article VI (commitment to pursue disarmament efforts), the Conference was unable to adopt a final declaration.


18. The question of a comprehensive test-ban treaty continued to be most actively pursued on the agenda of the international community following the Fourth Review Conference. In this connection, the States parties, both within and outside the framework of the United Nations, began to pursue several different approaches which, in their respective views, could advance the achievement of such a treaty. In the first place, this included action in the General Assembly. As in previous years, the Assembly adopted various resolutions that underlined the importance of the issue and called for various specific steps. Another approach, which attracted a great deal of attention, was a proposal to convert the Partial Test-Ban Treaty into a comprehensive test-ban treaty through an amendment procedure. Furthermore, in a major development, nuclear-weapon States were able to declare unilateral voluntary moratoriums on testing. Finally, the Conference on Disarmament, in its consideration of the issue, made a significant breakthrough regarding the mandate of its Ad Hoc Committee on a Nuclear Test Ban which enabled it to begin full-fledged negotiations. Some of these developments were a direct result of substantively changed circumstances in international relations characterized by unprecedented improvements in the relationship between the major military Powers.

A. General Assembly

19. The consideration by the General Assembly at its forty-fifth session, in 1990, of the question of the cessation of nuclear-weapon tests reflected, to a large extent, the same differences in position on the issue which had characterized the work of the Fourth Review Conference earlier that year. As a result, the Assembly, as in previous years, adopted two resolutions on the subject-matter which placed different emphasis on various aspects and methods of achieving this objective. The two resolutions were initiated by Western non-nuclear-weapon States and non-aligned States, respectively. Some nuclear-weapon States cast a negative vote on both resolutions, some abstained and one voted in favour. The vote was very much a reflection of the generally held positions of those States on this issue.

20. Considerable progress took place in the consideration of the question at the forty-sixth session of the General Assembly, in 1991. For the first time in nearly 20 years, the Assembly was able to adopt one single resolution on a comprehensive test-ban treaty, calling for the early discontinuance of all nuclear-test explosions for all time. This was the result of efforts which had begun at the previous session. It proved possible owing to further convergence of positions among the non-nuclear-weapon States. Some nuclear-weapon States, however, continued to have reservations about specific provisions of the resolution and voted against it.

21. In 1992, at its forty-seventh session, the General Assembly again adopted one single resolution on the subject, although with one negative vote. A major breakthrough occurred at the forty-eighth session when the Assembly not only adopted one single resolution on the subject, but also for the first time, without a vote. This was made possible owing to an agreement reached in the Conference on Disarmament in August 1993 to begin negotiations on the issue. Thus, in resolution 48/70 of 16 December 1993, the Assembly welcomed the decision of the Conference, called upon all States to support the negotiation and urged the Conference "to proceed intensively, as a priority task, in its negotiation of such a universal and internationally and effectively verifiable treaty". At its forty-ninth session on 15 December 1994, the General Assembly adopted, once again by consensus, resolution 49/70, in which it urged all States participating in the Conference on Disarmament to negotiate intensively "as a high priority task", and to conclude a universal and multilaterally and effectively verifiable comprehensive nuclear test-ban treaty which contributed to nuclear disarmament and the prevention of the proliferation of nuclear weapons in all its aspects. The five nuclear-weapon States were among the sponsors of the draft resolution.

22. In the course of the deliberations on this issue in the General Assembly during this period, a number of States expressed the view that there was no "linkage" between the nuclear test ban and a moratorium on testing unilaterally declared by nuclear-weapon States, on the one hand, and the question of the indefinite extension of the non-proliferation Treaty, on the other.

B. Amendment Conference

23. Following up on an earlier initiative launched by Mexico in 1985, the General Assembly, on 4 December 1990, acting on the proposal of a group of non-aligned countries, adopted resolution 45/50, on the convening of an Amendment Conference of the Partial Test-Ban Treaty. The Conference was convened at United Nations Headquarters from 7 to 18 January 1991 under the presidency of Indonesia. Of the Treaty's 117 parties, 100 participated. The Conference had received a report from the Preparatory Meeting of the parties to the Treaty for the organization of the Amendment Conference, held in May-June 1990, which served as the basis for its work. The principal topic of discussion at the Conference was the proposal to add a new article to the Treaty, article VI, as well as two protocols which would have the effect of converting the Treaty into an instrument banning all nuclear-weapon tests for all time. 8/

24. A majority of participating States favoured this course of action since, in their opinion, it provided the quickest possible way to achieve a complete cessation of nuclear testing. Other States, however, pointed to the difficulties of accepting the proposed approach and, therefore, did not consider it practical. The problem cited most frequently by the latter was that of verification of the ban on underground tests which, they thought, would not be adequately addressed in a simple amendment to the Treaty. With the amendment procedure, in the opinion of those States, the verification issue could not properly be resolved. In this connection, nuclear-weapon States and some non-nuclear-weapon States pointed to the Conference on Disarmament as the most proper venue for the negotiations of a comprehensive test ban.

25. Given this divergence of views, the Amendment Conference could not arrive at a substantive decision, nor reach agreement on its possible extension, reconvening or resumption. In acknowledging the complex and complicated nature of certain aspects of a comprehensive test-ban treaty, especially those with regard to verification of compliance and possible sanctions against non-compliance and considering that further work needed to be undertaken, the Conference, in the end, decided by 74 votes to 2 (United Kingdom and United States), with 19 abstentions (mostly Western States), to mandate the President to conduct consultations with a view to achieving progress on those issues and resuming the work of the Conference at an appropriate time. 9/

26. Pursuant to that decision, the President conducted consultations and in October 1992 an understanding was reached by a majority of the parties to the Treaty that a special meeting of States parties would be held in 1993. Its task would be to review the developments on the issue of nuclear testing and to take appropriate decisions.

27. At the special (informal) meeting held on 10 August 1993, there was broad agreement among States parties that the work on a comprehensive test ban in the different forums, and especially the Amendment Conference and the Conference on Disarmament, should be mutually supportive and mutually complementary. In this connection, the meeting welcomed the de facto moratoriums on nuclear tests declared by some nuclear States and their commitment to work expeditiously towards achieving a comprehensive test ban. The meeting further welcomed the decision of the Conference on Disarmament to give a negotiating mandate to its Ad Hoc Committee on a Nuclear Test Ban. The meeting also stated that it was essential that the President should work in close coordination with the Conference on Disarmament and the five nuclear Powers. 10/

28. During the forty-eighth session of the General Assembly, on 4 October 1993, a meeting of Ministers for Foreign Affairs and Heads of Delegation of the Movement of the Non-Aligned Countries was held at United Nations Headquarters, under the chairmanship of Indonesia. In the communiqué of the meeting, 11/ the participants underscored the value of the de facto moratoriums on nuclear tests and, at the same time, of the commitment of the nuclear-weapon States to work towards a comprehensive test-ban treaty. They endorsed the work of the Amendment Conference in seeking the discontinuance of all tests in all environments and for all time. They also endorsed the decision by the Conference on Disarmament to give its Ad Hoc Committee on a Nuclear Test Ban a mandate to negotiate such a ban. They further affirmed that the pursuit of this objective under the auspices of the Amendment Conference and the Conference on Disarmament was mutually supportive and complementary. They stressed the importance of the expeditious conclusion of a comprehensive nuclear test ban in view of the contribution it could make to nuclear disarmament and to nuclear non-proliferation.

29. Furthermore, in the Final Document of the Eleventh Ministerial Conference of the Movement of the Non-Aligned Countries, held at Cairo from 31 May to 3 June 1994, in the chapter on "Disarmament and international security", the Ministers welcomed the continuing efforts of the President of the Amendment Conference to ensure a complementary relationship between that forum and the Conference on Disarmament in the achievement of a comprehensive test-ban treaty. In that connection, the Ministers urged the Conference on Disarmament to conclude successfully a universal and effectively verifiable comprehensive test-ban treaty, without any provisions for exceptions, as a matter of the highest priority. 12/

C. Moratorium

30. The question of a moratorium on nuclear-weapon tests, a long-standing issue on the agenda of the international community, has achieved significant prominence since the 1990 Review Conference. In October 1991, President Mikhail Gorbachev, responding to an earlier initiative of President George Bush on a number of unilateral, related steps on nuclear arms control and disarmament and confidence-building measures, announced a series of steps that would be taken unilaterally by the Union of Soviet Socialist Republics. One of the measures announced was an immediate one-year unilateral moratorium on nuclear-weapon tests. He expressed the hope that other nuclear Powers would do the same.

31. In April 1992, France announced its decision to suspend the testing of nuclear weapons until the end of 1992. Later that year, on 24 September, the United States Congress decided that no underground test of nuclear weapons would be conducted after 30 September 1992 and before 1 July 1993. The legislation also placed limits on the number of tests to be permitted annually after 1 July 1993 and prohibited testing altogether after 30 September 1996, unless another State conducted a nuclear test after that date. The United Kingdom, which was conducting its own test at the test sites of the United States, accepted the moratorium as well. Following the dissolution of the Soviet Union, the Russian Federation decided to extend its one-year unilateral moratorium to 1 July 1993.

32. In July 1993, the new United States Administration announced its decision to extend the moratorium on nuclear testing, at least until the end of September 1994, as long as no other nation tested, and called upon the other nuclear Powers to do the same. If those nations were to join the United States in observing the moratorium, the Administration said, the five nuclear Powers would be in the strongest possible position to negotiate a comprehensive nuclear test ban and to discourage other nations from developing their own nuclear arsenals. 13/ Also in July 1993, the Russian Federation announced the extension of its moratorium "for as long as the moratorium declared by other States is observed de jure and de facto by them". 14/ In February 1995, the Russian Federation reiterated its commitment to adhere to the indefinite trilateral moratorium on nuclear testing as long as similar moratoriums announced by other nuclear Powers were adhered to.

33. In a further development, in March 1994, President Bill Clinton informed the Congress of the United States that he was extending the moratorium on nuclear testing by the United States until the end of September 1995. The President would decide in 1995 whether to extend further the moratorium. 15/ Meanwhile, the United Kingdom announced that it would not test as long as the United States moratorium was in force. In another development, in April 1994, French President François Mitterrand stated that the question of the resumption of France's nuclear tests depended on the actions of other nuclear Powers: if they did not resume testing, neither would France. On 29 January 1995, the United States declared that, assuming a comprehensive nuclear test-ban treaty would be signed by 30 September 1996, it decided to extend its current moratorium on nuclear tests until the comprehensive nuclear-test-ban treaty entered into force. 16/

34. The last test conducted by the Soviet Union took place on 24 October 1990. France has not tested since 15 July 1991; the United Kingdom since 26 November 1991; and the United States since 23 September 1992. 17/

35. The Government of China, on several occasions, stated that it had always exercised utmost restraint on nuclear testing and the number of the nuclear tests it had conducted was extremely limited - the least among the nuclear-weapon States. It further stated that it supported the early conclusion of a comprehensive nuclear test-ban treaty and it would take an active part in its negotiating process and work together with other countries to conclude the treaty as soon as possible, no later than 1996. After the treaty entered into force, China would abide by it and would carry out no more nuclear tests. 18/

36. Since the Fourth Review Conference in 1990, the status of nuclear-weapon tests conducted has been as follows: 18 tests were carried out in 1990; 14 tests in 1991; 8 tests in 1992; 1 test in 1993; and 2 tests in 1994. Of the total of 43 nuclear-weapon tests, China conducted 7 tests, France 12, the Soviet Union 1, the United Kingdom 2, and the United States carried out 21 tests.

D. Conference on Disarmament

37. Following the decision on the mandate of the Ad Hoc Committee on a Nuclear Test Ban reached at the 1990 session, in which the Ad Hoc Committee was requested to initiate, as a step towards achieving a nuclear test-ban treaty, substantive work on specific and interrelated test-ban issues, including structure and scope as well as verification and compliance, the work of the Conference on Disarmament on this issue gained a new impetus. The consideration, at first, touched in broad terms upon the diverse aspects of such a treaty including, in particular, sensitive issues of the verification provisions.

38. In all these considerations, the questions concerning verification provisions attracted the greatest attention. It was generally recognized that, in order to ensure compliance with a future test ban, an effective, internationally applicable verification system would be required. Some of the issues were: the substantial role that a global seismic monitoring network would have, especially in the underground test environment; the use of additional non-seismic verification technologies for the detection of nuclear tests in various environments, particularly in relation to evasion scenarios, and the possible use of such techniques for the detection of pre-testing preparations; the costs of a future verification system vis-à-vis its capabilities; the implementing agency, its powers and function and cost; the close interrelationship of applicable verification techniques and the scope of obligations under the treaty; and a possible mix of national and international means of verification, taking into account cost-effectiveness.

39. Continuing its work on the subject of verification, the Ad Hoc Group of Scientific Experts to Consider International Cooperative Measures to Detect and Identify Seismic Events (see para. 15 above) completed a comprehensive seismological evaluation of its second technical test (GSETT-2). 19/ Taking into account that evaluation, it also focused on the reassessment of the initial concept of a global system for the exchange of seismic data worked out in 1989. 20/ The Group further discussed the schedule and plans for developing, testing and evaluating an experimental international seismic monitoring system. This effort, referred to as GSETT-3, is under way and the Group intended to start full-scale testing on a global scale by 1 January 1995.

40. A new, substantively different stage in the work of the Conference on Disarmament on this issue was reached towards the end of its 1993 session. On 10 August 1993, the Conference took a consensus decision to give its Ad Hoc Committee on a Nuclear Test Ban a mandate to negotiate a comprehensive test-ban treaty. It also entrusted the Chairman of the Committee to initiate a process of consultations with a view to reaching agreement on specific wording for a negotiating mandate and on organizing the negotiations to begin in January 1994.

41. Also during the Conference on Disarmament's 1993 session, Sweden submitted for further consideration a draft comprehensive test-ban treaty 21/ and a further revised draft during the inter-sessional work. 22/ Subsequently, Australia also submitted a draft which dealt with a structural outline of a comprehensive test-ban treaty 23/ and later submitted a resource paper on draft treaty elements.

42. The results of the inter-sessional consultations regarding the mandate were approved by the Conference at its first meeting, on 25 January 1994. The decision of the Conference reads in full as follows:

"In the exercise of its responsibilities as the sole multilateral disarmament negotiating forum of the international community, the Conference on Disarmament decides to re-establish an Ad Hoc Committee under item 1 of its agenda entitled 'Nuclear test ban', and to give priority to its work.

"The Conference directs the Ad Hoc Committee to negotiate intensively a universal and multilaterally and effectively verifiable comprehensive nuclear test-ban treaty, which would contribute effectively to the prevention of the proliferation of nuclear weapons in all its aspects, to the process of nuclear disarmament and therefore to the enhancement of international peace and security.

"Pursuant to its mandate, the Ad Hoc Committee will take into account all existing proposals and future initiatives, as well as the work of the Ad Hoc Group of Scientific Experts to Consider International Cooperative Measures to Detect and Identify Seismic Events. The Conference requests the Ad Hoc Committee to establish the necessary working groups in order to carry forward effectively this negotiating mandate: these should include at least two working groups, one on verification and one on legal and institutional issues, which should be established in the initial stage of the negotiations, and any others which the Committee may subsequently decide upon.

"The Ad Hoc Committee will report to the Conference on Disarmament on the progress of its work before the conclusion of the 1994 session." 24/

43. On 2 February 1994, the Conference took decisions on organizational aspects of its work, inter alia, by appointing the Chairman of the Ad Hoc Committee on a Nuclear Test Ban and establishing two Working Groups to deal with verification and legal and institutional arrangements, respectively. The Ad Hoc Committee reported on its work to the plenary of the Conference on 7 September 1994. 25/

44. The results of the negotiations in the Ad Hoc Committee on the draft treaty are included in a rolling text which comprises three parts: part 1 represents the present stage of the elaboration of the treaty provisions which command a certain degree of consensus at this stage; part 2 contains provisions which need more extensive negotiation; and part 3 comprises a list of documents containing proposals of delegations.

45. As recommended in its report to the Conference on Disarmament, 26/ the Ad Hoc Committee held an inter-sessional meeting from 28 November to 16 December. Working Group 1 focused on the verification provisions of the Treaty and the international monitoring system, and Working Group 2 on issues relating to the Organization for the implementation of the treaty. In the framework of the inter-sessional meeting, a meeting of experts was held on various aspects of on-site inspections, a significant component of the future verification regime. The results of the work undertaken during the inter-sessional meeting are contained in a report by the Ad Hoc Committee to the Conference on Disarmament. 27/

46. Upon resuming its work on 31 January 1995, the Conference on Disarmament re-established the Ad Hoc Committee on a Nuclear Test Ban with the same mandate as approved on 25 January 1994.

47. In connection with the work of the Ad Hoc Committee, at the opening meeting of the Conference, the United States referred to its decision to extend its moratorium and also announced that it would withdraw its proposal for a special "right to withdraw" from the Treaty 10 years after its entry into force. 28/


1/ Source: United States Department of Energy, Statement of 7 December 1993. The figure of 1,051 includes 204 unannounced nuclear tests between 1963 and 1990.

2/ The figure includes additional tests announced by the Soviet authorities in September 1990 for the period 1949-1990. Source: SIPRI Yearbook 1993, chap. 6, appendix 6A, pp. 254-257.

3/ CD/PV/658, p. 14, 5 August 1993.

4/ SIPRI Yearbook 1993, chap. 6; appendix 6A, pp. 254-257.

5/ The instruments of ratification of the two Treaties were exchanged on 11 December 1990.

6/ CD/PV.622, p. 7, 26 May 1992.

7/ CD/130.

8/ The report of the Amendment Conference was issued as document PTBT/CONF/13/Rev.1.

9/ Ibid., part I, introduction, para. 26.

10/ A/48/381, annex.

11/ A/48/484-S/26552, annex.

12/ A/49/287-S/1994/894, annex, chap. I, paras. 51 and 52.

13/ CD/1205.
14/ CD/PV.658, p. 17, 5 August 1993.

15/ CD/1249.

16/ CD/PV.693, p. 20, 31 January 1995.

17/ Arms Control Today, November 1993, p. 29.

18/ A/C.1/48/3, annex.

19/ CD/1185, annex.

20/ CD/903.

21/ CD/1202.

22/ CD/1232.

23/ CD/1235.

24/ CD/1238.

25/ CD/1273/Rev.1.

26/ Official Records of the General Assembly, Forty-ninth Session, Supplement No. 27 (A/49/27), chap. III, sect. A.

27/ CD/1284.

28/ CD/PV.693, p. 20, January 1995.