The US government has expressed doubt about the suitability of corporate partnership with an Indian state aerospace company as Boeing and Lockheed Martin bid to supply New Delhi with 126 strike fighters.

The US is pitching for what is one of the world’s largest military contracts, worth $11bn. Boeing’s F/A-18 Super Hornet and Lockheed’s F-16 Super Viper are vying with Eurofighter Typhoon, Saab’s Gripen, Dassault’s Rafale and Russia’s MiG-35 in a competition expected to be decided this year.

Any winning bidder would have to partner Bangalore-based Hindustan Aeronautics Limited, which has in the past worked closely with Russian, British and French defence companies and produced an estimated 3,600 aircraft and helicopters. HAL’s turnover last year was $2.5bn.