Asked about the delay in the supply of further batches of the combat jets to India, Fernandes told newspersons here: ``We have asked for slight changes in configuration of the aircraft to meet new needs of the Air Force.''

Fernandes discounted reports that the delivery programme of the long-range warplanes had suffered a setback because of the suggested modification. Sukhoi-30 jets can carry eight tonnes of weapons.

``There is now a revised scheduled for the delivery of the aircraft. There might be some slight delay but the entire deal is on course,'' the Minister said.

India has so far received eight Su-30 fighters from Russia as part of a Rs 6,330-crore deal signed in November 1996 for supply of 40 contracted warplanes. The bomber version of Su-30 and the upgraded versions of the combat jet under Indian specifications were in the pipeline, Defence sources said.

Fernandes declined to go into details about the modifications in Su-30 sought from Russia and only said it could involve changes like converting the cockpit from a single-seat version to a two-seater one.

Meanwhile, the Indian Space Research Organisation (ISRO) today received the first of the seven cryogenic engines from Russia for the launch of the Geosynchronous Satellite Launch Vehicle (GSLV).

ISRO said that with the arrival of the cryogenic stage, the launch of the GSLV has been planned for the third quarter of 1999.

ISRO said the cryogenic stage formed the third stage of the GSLV and the unit received today was the first of the seven units being supplied by Russia. The remaining units would be delivered at the rate of one every six months.

The other systems of GSLV were in various stages of readiness and the launch campaign for the first developmental flight of GSLV was expected to commence in the second half of 1999. The launch would take place after the PSLV C-2 launch which would carry the Indian Remote Sensing-P4 Oceansat payload besides two commercial payloads.