Barely a month after carrying out successful tests of Interceptor missiles, India is in talks with a leading American aerospace firm to apparently seek collaboration to develop a robust ballistic missile defence (BMD) system.

"We are still in touch with Defence Research and Development Organisation (DRDO) officials," Dennis D Cavin, vice-president, International Air and Missile Defence Strategic Initiatives (IAMDSI) of Lockheed Martin said.

The IAMDSI is developing the PAC-III anti-missile system for the US.

US experts said New Delhi could be looking for Washington's help and that of other nations in developing crucial sub-systems for the BMD.

Cavin, who would be flying to India next month, said India could be looking at US help to develop "hit-to-kill" technology for its interceptor missiles.

The American official said he would be meeting Dr V K Saraswat, who is known as the father of the Indian interceptor missile programme.

US is developing a multi-layered anti missile defence system of which, PAC-II, III and THAAD would form essential components.

While, the PAC-II and III systems are being deployed to tackle the threat from air-breathing cruise missiles and Unmanned Aerial Vehicle (UAV) threats, the THAAD system is developed to take care of threats from "Eco and Endo" atmospheric ballistic missile threats.

The Americans, who have already deployed PAC-II and III systems, are likely to deploy THAAD system between 2009-2010 to give cover to US troops deployed overseas.

In his briefings to the media, DRDO scientist Dr Saraswat had said that India's interceptor missiles had used "proximity fragmentation" in its missile interception programme.

Cavin said that US approach was to seek a direct 'hit-to-kill' method in destroying incoming missiles.

It is possible that New Delhi might be looking at acquiring such a capability for its missile interception programme, Cavin said.

"Our doors of co-operation with India on the BMD system are open," the US official said.

The Terminal High Altitude Area Defence (THAAD) missile system has been described by Lockheed officials as top layer of the proposed US ballistic missile system.

Cavin, the company's leading missile man, said so far 24 flight tests have been carried out, both in Eco and Endo modes, of which 21 had hit the bull's eye.

"THAAD is a vital keg in our missile defence system," another top US missile expert said.

'It has the capability to intercept all short, medium and high altitude incoming missiles," she said.

The US army has recently ordered induction of two firing units of the THAAD system, comprising six launchers, each carrying 24 missiles, equipped with battery controlled and a radar station.

Though Washington has offered to sell PAC II and III BMD systems to India, it hasn't said anything on whether THAAD could be made available to India.

"I won't challenge it," Cavin said on India's attempt to develop its own indigenous BMD system.

He said the US was willing to co-operate in giving final shape to such a system for India, including collaborating in development of key subsystems.