Turkey on Friday asked the US to scrap observation posts in northern Syria aimed at helping prevent clashes between Turkish forces and a Kurdish militia backed by Washington.
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 militia which Ankara regards as a "terrorist offshoot" of the outlawed Kurdistan Workers' Party (PKK).
Akar also asked Jeffrey to stop the American collaboration with the YPG.
Syria's long-oppressed Kurdish minority has established a semi-autonomous region in the north of the country, which has been wracked by conflict since 2011.
Turkey refuses to recognise the territory on its border, fearing it will stoke the separatist ambitions of Kurds in its own country.
Ankara has carried out two operations against Kurdish forces since 2016, the last against the border enclave of Afrin, which it seized in March and is now controlled by pro-Turkish Syrian rebels.