Circumstantial evidence indicates the intruding spy craft mostprobably is of Chinese make as Pakistan is understood to haveacquired an unspecified number of such craft of Chinese origin.
Earlier, there were reports that the unmanned spy plane may beof Israeli origin and Pakistan may have come about it in the internationalarms bazaar.
Defence officials claim Pakistan has acquired remote-control pilotlessaircraft of Chinese origin. These have piston engines.
These craft have a maximum speed of 205 km per hour and can flyup to a maximum altitude of 3,200 metres.
A handful of countries have so far acquired from Israel, US andFrance the know-how to build such planes.
Australia, China and Russia are other countries which build suchplanes of eight-metre length.
China is understood to have an active programme to develop theremote-control espionage craft. The Chinese planes are up to ninemetres in length.
The planes can carry out surveillance because of the cameras,night-vision devices and other sophisticated sensors on board.
The airborne craft are highly manoeuvrable and use the capabilityto spot targets. The information they receive is then relayedlive through a data link to an airborne post or ground station.
Battlefield surveillance is the prime objective of such planesalso called UAVs or unmanned aerial vehicles.
The South Western Air Command has been reporting some intrusionsinto Indian airspace in the neighbourhood of Bhuj and Nalia inGujarat, adjoining the western border, in the first half of January.
These intrusions were made by small pilotless and remote-controlaircraft, originating on the Pakistan side of the border.
One such plane was sighted near Bhuj airport on the morning ofJanuary 15 and was fired at by the Indian Air Force.
Simultaneously, air defence measures were also initiated by theIAF to prevent such intrusions.
Though the intruding plane was hit, its debris have not been locatedso far. A protest was lodged through diplomatic channels withPakistan regarding intrusions of the Indian air space, which werein violation of the bilateral agreement between the two countrieson prevention of airspace violations.
Pakistan has, however, denied any intrusions by its aircraft.