BEIRUT (AP) — The main Syrian Kurdish militia has invited government troops to take control of the flashpoint northern town of Manbij to prevent a Turkish attack.

The People's Protection Units, or YPG, made the appeal Friday in a tweet. The Syrian Observatory for Human Rights is reporting that Syrian government forces have been massing on the edges of Manbij, a front line between Kurdish-led forces and Turkey-backed fighters to the west.

It is not yet clear whether U.S. troops, which had patrolled the area, remain in place or have withdrawn. There was no immediate response from the U.S-led coalition.

Turkey had threatened a military operation against Manbij to remove the Kurdish-led forces there. Turkey views the YPG as a terrorist group.

The threats triggered the U.S. announcement of withdrawing troops from Syria.