Turkey-backed Syrian rebels pledged on Friday to back a potential cross-border offensive that Ankara has threatened to mount against Kurdish fighters in northeast Syria.
Ankara and Washington have agreed to set up a zone in northeast Syria along the border with Turkey, which wants to expel the Syrian Kurdish YPG militia from the frontier.
Turkey has accused the United States, which helped the YPG defeat Islamic State militants, of moving too slowly to establish the zone. The two countries are also at odds over how far it should extend into Syria and who should control it.
Turkey wants the zone to go 30 km (19 miles) inside Syria and has repeatedly warned it could launch its own operation.