The US has voiced “strong opposition” to Turkey's plans for a fresh ground invasion of Syria.
Secretary of Defence Lloyd Austin said he spoke with Turkish Defence Minister Hulusi Akar on Wednesday, urging Ankara to de-escalate as it warns of an impending ground invasion of its southern neighbour.
Mr Austin “shared the department's strong opposition to a new Turkish military operation in Syria”, the Pentagon said.
He also “expressed concern” over air strikes in the north-east, some of which “directly threatened US personnel” working with the Kurdish-led Syrian Democratic Forces to defeat ISIS.
Turkey has renewed its aerial offensive in northern Syria following a deadly bombing in Istanbul, which it blamed on Kurdish militants in Syria's north-east.
President Recep Tayyip Erdogan has said that Turkey will launch a ground invasion “as soon as possible” and warned that its aerial attacks on the Kurds are just the beginning.
Attacks have been reported on key oilfields and Al Hol camp, which holds thousands of ISIS-linked families and is guarded by Kurdish forces. Germany has urged restraint as Mr Erdogan reiterated plans to send troops into Syria.
Turkey has carried out several military operations against Syrian Kurds, claiming the SDF, which rules most of north-east Syria, is an offshoot of the Kurdistan Worker's Party (PKK) and a threat to its national security. Its last major operation in 2019 displaced more than 300,000 civilians and saw Ankara seize control of a stretch of land in the north-east.
Turkey and its Syrian proxies also control Afrin, in north-west Syria, and Ankara regularly strikes Kurdish positions in neighbouring Iraq.
On Tuesday, a US official told The National that a Turkish ground invasion would not solve Ankara's security concerns.
SDF chief Mazloum Abdi has urged stronger action from Washington, one of its key allies, after Ankara sent troops to its southern border.
Anti-ISIS operations have been suspended amid the Turkish attacks, Kurdish officials said. While the terror group was driven out of its last Syrian bastion of Baghouz in 2019, in continues to launch insurgent attacks and often targets SDF positions across the north-east.