YEREVAN, JUNE 30, ARMENPRESS. A US senator has prepared a proposal to buy Russian-made S-400 air defense systems from Turkey in a bid to overcome the impasse between Washington and Ankara over Turkey’s participation in a program to produce F-35 Lightning II fifth-generation fighter jets, TASS reports citing Defense News.

According to Defense News, Senate Majority Whip John Thune has proposed an amendment to the 2021 National Defense Authorization Act (NDAA) that would allow the purchase to be made using the US Army’s missile procurement account.

Meanwhile, Senate Foreign Relations Committee Chairman Jim Risch has introduced a tougher amendment, which envisages slapping Turkey with sanctions under CAATSA (Countering America's Adversaries Through Sanctions Act) 30 days after NDAA enters force.

According to the paper, although Thune and Risch are both influential senators, "there’s no guarantee either of their amendments would receive consideration to be included in the massive NDAA · or, if passed into the Senate bill, that they would survive negotiations with the House."

Russia announced in September 2017 that it had signed a $2.5 billion deal with Turkey on the delivery of S-400 anti-aircraft missile systems to Ankara. Under the contract, Ankara received a regiment set of S-400 air defense missile systems (two battalions). The deal also envisages partial transfer of production technology to the Turkish side.