It is the first encounter since July between Sharaa and Abdi, head of the US-backed, Kurdish-led Syrian Democratic Forces (SDF), and comes as implementation of a March deal between the two on integrating Kurdish institutions in the country's north and northeast into the state has largely stalled.

A separate source close to the meeting, requesting anonymity, said US envoy for Syria Tom Barrack and Admiral Brad Cooper, head of the US military's Central Command, were also attending.