Turkey on Friday asked the US to scrap observation posts in northern Syria.
Defence Minister Hulusi Akar made the demand during a meeting with James Jeffrey, the US Special Envoy to Syria, his ministry said in a statement.
US Defense Secretary Jim Mattis had said that Washington wanted the observation posts to help minimise tensions between Turkish forces and Washington's Kurdish allies, including the Syrian Kurdish YPG militants.
Akar also asked Jeffrey to stop the American collaboration with the YPG.
Turkey and the United States have agreed to speed up efforts to put in place an agreement on Syria's Manbij by the end of the year, a working committee between Ankara and Washington said on Friday.
Earlier this year, Turkey and the United States reached a deal over Manbij, after months of disagreement, under which the YPG is to completely withdraw from the town.