Turkish troops have begun an offensive in northern Syria, which could bring them into direct conflict with Kurdish-led forces allied to the United States, the BBC reports.
The move was announced by Turkey’s President Recep Tayyip Erdogan.
Turkey wants to create a “safe zone” cleared of Kurds that will also house some of Turkey’s 3.6 million Syrian refugees.
Donald Trump withdrew US troops ahead of the action but says Turkey may face economic consequences.
The Kurds were key US allies in defeating the jihadist group Islamic State (IS) in Syria.
Announcing the offensive, Mr Erdogan said on Twitter: “The Turkish Armed Forces, together with the Syrian National Army [rebel groups backed by Turkey], just launched #OperationPeaceSpring” against Kurdish militias and the Islamic State group in northern Syria.”
“Our mission is to prevent the creation of a terror corridor across our southern border, and to bring peace to the area,” he added.
“We will preserve Syria’s territorial integrity and liberate local communities from terrorists,” Erdogan continued.