ANKARA, TURKEY - NOVEMBER 25: The S-400 air defence system from Russia is activated for testing at Turkish Air Force's Murdet Air Base on November 25, 2019 in Ankara, Turkey. Turkey purchased the anti-aircraft weapons system from Russia over the objections of the United States, which has threatened to sanction Turkey and exclude it from its F-35 fighter jet program. The U.S. fears that the F-35, which is designed to evade such anti-aircraft systems, will be compromised if Turkey deploys both. (Photo by Getty Images)
The S-400 air defence system from Russia is activated for testing at Turkish Air Force's Murdet Air Base in Ankara, Turkey. Getty Images

Turkey tests S-400 Russian missile system with US jets, defying Washington