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.

FILE - Russian S-400 air defense missile systems are on display during a rehearsal for the Victory Day military parade in Red Square in Moscow, Russia, May 7, 2017.
Erdogan Recommits to Buying Russian Missiles Despite US Warnings
Turkish President Recep Tayyip Erdogan has reaffirmed his commitment to buy a Russian missile system in the face of renewed warnings from NATO ally the United States. The prospect of a clash between Ankara and Washington has grown, with Moscow moving the delivery date for the missiles to this year.Erdogan is blaming Washington for the deepening crisis over the procurement of Russia's S-400 missile system.

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.