Turkey to Send Home Russian S-400 Missile System Experts in Signal to U.S. – Reports June 2, 2021 The U.S. had sanctioned Turkey over its purchase of the Russian-made air defense system for a reported $2.5 billion. Sergei Malgavko / TASS Turkey will send home Russian military experts helping it operate the Russian-made S-400 air defense system but will not budge on the key U.S. demand to scrap the deal altogether, Bloomberg reported this week. Russia delivered its first of four S-400 batteries to NATO member Turkey in July 2019 as part of a reported $2.5 billion deal. In response, the United States expelled Ankara from its F-35 fighter jet program and hit Turkey’s military procurement agency with an asset freeze and visa restrictions in addition to banning it from U.S. export licenses.