Turkish President Tayyip Erdogan told U.S. President Donald Trump in a phone call on Wednesday that U.S. troops should withdraw from northern Syria’s Manbij region, Turkey’s foreign minister said on Thursday.

On Wednesday, prior to his phone call with Trump, Erdogan said Turkey would extend its military operation in Syria to the town of Manbij, a move that could potentially bring Turkish forces into confrontation with those of their NATO ally the United States.

Speaking to reporters following a news conference with his Austrian counterpart, Mevlut Cavusoglu also said Turkey would not attack Syrian government forces unless they made a move against Turkey

The U.S. should “stop supporting terrorists” if it wants to avoid a possible confrontation with Turkey in Syria, Deputy Prime Minister Bekir Bozdag said on Thursday as Ankara pressed on with its incursion against a Kurdish militia there.

“Those who support the terrorist organisation will become a target in this battle,” he told broadcaster A Haber in an interview. “The United States needs to review its solders and elements giving support to terrorists on the ground in a way to avoid a confrontration with Turkey.”