The YPG withdrew from some border positions in recent days, proving it is serious about ongoing talks, the Kurdish-led authority running much of north and east Syria also said.

Turkey and Washington agreed this month to create a coordination centre for a planned “safe zone” in northeast Syria along the border, including joint patrols. But they gave few details on the zone’s size or the command structure of the forces to operate there.

A main point of friction has been how deep the zone would extend into northeast Syria under the deal, which includes joint patrols and will come into effect in phases.

SDF spokesman Mustafa Bali told Reuters the width of the strip would vary along the border between 5 and 14 km and will include rural areas or military positions, not cities or towns.

The YPG and SDF will dismantle barricades “of defensive nature” there, and will hand over control to military councils of local fighters, he said.

Turkey has repeatedly said it would not tolerate any delays to the deal by U.S. officials, warning it will mount a cross-border offensive on its own to clear its borders if necessary.

Ankara has already sent its military twice into northern Syria to push the Kurdish fighters from its borders in recent years.

U.S. support for the YPG has enraged Turkey, which deems the militia a security threat linked to Kurdish insurgents at home.

The YPG spearheads the Syrian Democratic Forces (SDF) alliance, which controls north and east Syria, after defeating Islamic State militants with U.S. help.

Bali said Turkish and U.S.-led coalition forces would patrol the border strip but be based inside Turkey.

The deal creates “a security mechanism, not safe zone, that assuages Turkey’s claims of fearing over its national security,” he said.

The YPG already withdrew from the Tel Abyad and Ras al-Ain areas, the authority running the SDF region said. The move shows commitment to “reaching a solution through dialogue,” the statement said.

About 2,000 U.S. troops have been stationed in the SDF region for years, training and arming the fighters in the battle against Islamic State.

Reporter’s code: 50101