U.S. acting Defense Secretary Patrick Michael Shanahan said Turkey would not receive F-35 fighter jets if it proceeds with its purchase of Russian S-400 air defence systems, the Washington Examiner reported.

U.S. officials have repeatedly said the S-400s could be used by Russia to collect sensitive information on the F-35s if the two systems are used simultaneously. They have threatened to exclude Turkey from the F-35 programme and not deliver the 100 fighter jets it has ordered from the United States.

"There's no confusion on our part," Shanahan said at a House of Representatives’ Appropriations Committee hearing. "It's one or the other".

The U.S. Congress passed legislation last year to block the delivery of F-35 jets to Turkey if the Turkish government took delivery of the Russian missiles. Washington has also offered to sell Patriot air defence batteries to Turkey, of Ankara cancels the S-400 purchase.