Turkey on Thursday said it will intervene in Syria's Afrin and Manbij to counter the threat posed by the Kurdish People's Protection Units (YPG), describing as far from satisfactory US assurances playing down plans to create a border force made up of the Kurdish forces.
Foreign Minister Mevlut Cavusoglu told CNN Turk in an interview that Turkey would intervene in Afrin and Manbij to counter the YPG.
Washington's support of the YPG has infuriated Turkey, particularly after the US-led coalition said it would help set up a new 30,000-strong border force that includes the YPG.
US Secretary of State Rex Tillerson said on Wednesday he had met with Cavusoglu to clarify the issue and said it had been "misportrayed, misdescribed".
Although the Pentagon said late Wednesday it does not plan to create an "army," Cavusoglu stressed that "the establishment of a so-called terror army would cause irreversible damage in our relations ... it is a very serious situation.”
The Pentagon said the force is aimed at fighters from ISIS and maintaining stability in areas recaptured from the militants.
"Did this satisfy us in full? No, it did not," Cavusoglu told CNN-Turk.
Turkey accuses the YPG of being a branch of the outlawed Kurdistan Workers' Party (PKK) that has waged an insurgency in its southeast since 1984.