FILE - Russian S-400 surface-to-air missile systems are seen on display during a parade at Red Square in Moscow, Russia, May 9, 2015.
FILE - Russian S-400 surface-to-air missile systems are seen on display during a parade at Red Square in Moscow, Russia, May 9, 2015.

The top U.S. commander for Europe says he would recommend the United States not sell its high-tech F-35 fighter jet to Turkey, if Ankara moves ahead with plans to buy a Russian missile defense system.

 Gen. Curtis Scaparrotti, head of U.S. European Command, says Turkey should reconsider its plan to buy the S-400 from Russia this year or forfeit other future American military aircraft and systems. He says the S-400 surface-to-air missile defense system would be a threat to the F-35.

Erdogan Recommits to Buying Russian Missiles Despite US Warnings

Scaparrotti says U.S. officials are currently in Turkey explaining the consequences of the S-400 purchase.
 
The State Department in December approved the sale of a $3.5 billion Patriot missile defense system to Turkey. The F-35 delivery to Turkey has been delayed as negotiations about the S-400 continue.