Foreign Minister Mevlüt Çavuşoğlu and U.S. Secretary of State Mike Pompeo discussed recent developments in Syria in a phone call Tuesday, diplomatic sources have said.
The call came one day after President Recep Tayyip Erdoğan announced an imminent planned military operation to clear terrorists out of the areas east of the Euphrates River.
"It is time to realize our decision to wipe out terror groups east of the Euphrates," Erdoğan said at a Turkish Defense Industry Summit on Wednesday.
"Turkey will carry out a military operation in a couple of days," he said, adding that the target of the operation would never be American soldiers on the ground but the terrorists.
The U.S. has been providing support to the PKK's Syrian affiliate YPG under the pretext of fighting against Daesh, despite outcry from Ankara, who views the terrorist group's presence on its southern border as a grave threat.
Pentagon spokesman Commander Sean Robertson said any unilateral military action in northeast Syria would be a "grave concern", as it could potentially jeopardise US troops working with the YPG in the region.
"We would find any such actions unacceptable," he said in a statement.
Ankara has also called on the U.S. to uphold its end of the deal and show significant progress on the Manbij agreement reached in June. In line with the agreement, Turkey is expecting a complete withdrawal of the YPG terrorists from Manbij and its surrounding areas.
After repeated demands for Washington to end its support to the YPG, Ankara signaled that it may launch a major cross-border operation in the area stretching from the Euphrates River to the Iraqi border to clear the terrorist group from its border region.
Previously, Turkey targeted the YPG in two cross-border operations, Operation Euphrates Shield launched in August 2016 and Operation Olive Branch in January 2018, as well as through air and artillery strikes.
In its more than 30-year terror campaign against Turkey, the PKK — listed as a terrorist organization by Turkey, the U.S. and the EU — has been responsible for the deaths of some 40,000 people, including women and children.