Trump to confront Turkey about buying Russian defense system

President Donald Trump will confront Turkey's leader about his decision to buy a Russian air defense system when they meet this week at the White House amid strained relations between the two NATO allies.

Trump's national security adviser, Robert O'Brien, said Sunday that the United States is still "very upset" by the move to purchase the Russian S-400 system.

The US says the system is not compatible with NATO forces and could compromise the F-35 fighter jet program and aid Russian intelligence.

The Trump administration removed Turkey from the F-35 program in July.

O'Brien told CBS' "Face the Nation" that if Turkey doesn't get rid of the Russian system, Turkey will likely face U.S. sanctions backed by a bipartisan majority in Congress.

Trump is scheduled to meet with Turkish President Recep Tayyip Erdogan on Wednesday and NATO Secretary-General Jens Stoltenberg on Thursday.

Trump and Erdogan plan a joint news conference Wednesday afternoon.

"There's no place in NATO for the S-400," O'Brien said.

"There's no place in NATO for significant Russian military purchases. That's a message that the president will deliver to him very clearly when he's here in Washington."