The U.S. Senate added an important amendment to the defence-spending bill in May. The amendment to the National Defense Authorization Act, or NDAA, suggested removing Turkey from the F-35 advanced fighter jet programme and halt sales of the aircraft. The Senate asked the secretary of defence to submit an evaluation report to Congress within 90 days - during which time sales of F-35s to Turkey were suspended. The committee explicitly asked the Pentagon to detail the implications and impact of selling the F-35s to Turkey, considering the Turkish government also plans to purchase of Russian S-400 anti-aircraft missile systems.
The Senate was worried that sensitive information about the F-35s could be passed onto the Russian government through the S-400 defence systems.
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