Defence partnership with India strong, looking to make it ever stronger: Pentagon

America's defence partnership with India is strong and is looking to make it ever stronger, the Pentagon has said as it warned nations against purchasing military hardware from other countries that are designed to counter it's sophisticated fifth-generation aircraft.

The comments come a day after President Donald Trump has announced that the US would not sell the F-35 fighter jets to Turkey after Ankara purchased the S-400 missile defense system from sanctions-hit Russia.

"Our defense partnership with India I think is strong and we're looking to make it ever stronger," David J Trachtenberg, the deputy under secretary of defence for policy, told reporters at a news conference on Wednesday.

Trachtenberg was responding to a question on the impact on bilateral defence ties as India goes ahead with its decision to purchase S-400 missile defense system from Russia.

"Can you have a major defence partnership with India, which is going ahead with a decision to buy S-400?" he was asked.

"I think the message we are sending is that we want to make sure that other countries are not purchasing equipment that is designed to counter our sophisticated fifth-generation aircraft," Trachtenberg said. "The other message we're sending is that we are consistent in our approach on this."