Pentagon warns Turkey it loses F-35 if it buys S-400

Ankara will face economic sanctions if it goes ahead with the purchase of Russia's S-400 missile defense system, Acting U.S. Defense Secretary Mark Esper said.

Esper met with Turkish Defense Minister Hulusi Akar during a NATO meeting, delivering a message: If Turkey buys the Russian S-400 system, it will not be allowed to buy the high-tech F-35 fighter jet.

A senior defense official traveling with Esper said the two men had a frank and candid discussion, but the meeting resulted in no movement or change of position on either side, the AP reported.

The U.S. has already stopped training Turkish pilots on the F-35, and given Ankara until the end of July to get its personnel out of the U.S.