Washington: The US on Wednesday offered India partnership in the development of the world's most advanced flying machine, the F-35 Joint Strike Fighter, months after losing the lucrative USD 10 billion contract for 126 war planes.

Acknowledging that India's recent decision not to opt for America's F-16 and F-18 fighters was a "setback", the Pentagon said it is still interested in selling its top notch fighters to India.

"Despite this setback, we believe US aircraft, such as the Joint Strike Fighter (JSF), to be the best in the world," the Pentagon said in a nine-page report to the Congress.

"Should India indicate interest in the JSF, the United States would be prepared to provide information on the JSF and its requirements (infrastructure, security, etc) to support India's future planning," the Pentagon said in a one-of-its kind report on India submitted to the US Congress.

The F-35 is a fifth generation all-stealth fighter being developed by US armament giant Lockheed Martin in a joint consortium with eight other countries -- the UK, Italy, the Netherlands, Turkey, Canada, Denmark, Norway and Australia.

The F-35 Lightning II boasts advanced airframe, autonomic logistics, avionics, propulsion systems, stealth and firepower at the most affordable cost.

The US has already undertaken some test flight of the fighter. F-35 is the only other 5th generation aircraft to fly in the world besides the F-22 Raptors. Washington has refused to share the Raptor technology with any other nation, even its closest allies the UK and Israel.

India has demonstrated keenness to expand its air power and the 126 MMRC deal is part of efforts to upgrade its air inventory. The European consortium EADS fighter Typhoon and
French fighter Rafale have been shortlisted for the contract.

India is also keen to acquire the 5th generation fighter technology and signed a deal with Russia for development of the Sukhoi 5th generation fighter aircraft.

Though the US lost the race for fighter jets in India, the Pentagon report noted that in less than a decade, starting at zero, the foreign military sales to India have shot up to approximately USD 6 billion. The sales include C-17 and C-130J transport aircraft, TPQ-37 fire-finding radars, Self-Protection Suites (SPS) for VVIP aircraft, specialized tactical equipment, Harpoon missiles, Sensor-Fuzed Weapons, and carrier flight and test pilot school training.

The Pentagon report indicated the Obama administration's keenness for continually looking for ways to expand defence cooperation with India.

The US "has taken many steps in recent years to facilitate science and technology and research and development cooperation with India. In doing so, we have signalled our unambiguous intent to pursue cooperative opportunities on increasingly sophisticated systems," Pentagon said.

"As our relationship continues to mature, we expect co-development of armaments to become a reality," it said.

Over the next five years, US will continue to establish itself as a reliable defence supplier to India and look for opportunities to enable further training and exchanges between the militaries as India continues its military modernisation.

"The Department of Defence, along with the Departments of State and Commerce, will advocate for US solutions to Indian defence needs. We recognise that India is also seeking to build its own indigenous defence industry, and is looking for the best technologies to use in its defence sector," Pentagon said.