Scientific Adviser to defence minister Dr V K Aatre told rediff.com that surface-to-air short-range Akash missile will go for trials in the early part of next year.

"Akash has done well in preliminary flight tests though its field trials are yet to be conducted. There has been some delay in making it operational," Aatre admitted.

Also Read India building unmanned underwater vehicle: Aatre The saga of Light Combat Aircraft LCA breaks sound barrier during test flight Vajpayee names LCA as 'Tejas' Kaveri engine will catapult India

He rejected media reports that the Indian Army and the Indian Air Force were set to acquire SAM missiles from abroad because of delays in the Akash project.

"The army and IAF have been involved all along in our missile projects. Unless we have a series of successful field trials, we can't give them for user trials to the two defence services," Aatre said.

Similarly the anti-tank Nag missile, he said, will go for field and user trials next year.

Referring to the controversy over the status of Trishul missile, Aatre said it has been 'put back in the R&D mode to conduct more field trials'.

Aatre also said the maiden flight of the first prototype vehicle (PV-1) of Tejas, the indigenous Light Combat Aircraft, will be made by September-end.

"PV-1 will fly by either September middle or by the end…" Aatre said, ahead of a review meeting of the LCA, to be held in Bangalore later this week.

He said the review meet would also decide on LCA's second Technology Demonstrator's (TD-2) attempt to break the sound barrier.

It may be recalled that the TD-1 reached a speed of Mach 1.2 on August 1, making it the country's first indigenously built fighter aircraft to break the sound barrier.

He said the indigenous Kaveri engine was undergoing high altitude tests in Russia and in about three years would be fitted in an LCA for further tests.