Earlier, Ankara hinted that it may turn to Russia for advanced aircraft if Washington failed to honour its commitment to sell it its Lockheed Martin F-35 fighters, ONA reports quoting sputniknews.
The US' F-35 warplane cannot operate in the same airspace as the Russian-made S-400 air defence system and Turkey knows this, US Secretary of State Mike Pompeo has told US lawmakers at a hearing Wednesday.
"It is not possible to both fly the F-35 in space where the S-400 is significantly operable," Pompeo said, speaking to members of the Senate Foreign Relations Committee. Washington has relayed this warning to Turkish authorities and defence officials, he added.