The commander of a Kurdish-led force in Syria said on Sunday the country's interim president must hold the perpetrators of communal violence in Syria's coastal areas to account, accusing Turkey-backed factions of being primarily behind the killings.

The head of the Syrian Democratic Forces (SDF), Mazloum Abdi, said in written comments to Reuters that Ahmed al-Sharaa must intervene to halt "massacres", adding factions "supported by Turkey and Islamic extremists" were chiefly responsible.

Syrian security sources have said at least 200 of their members were killed in clashes with former army personnel owing allegiance to toppled leader Bashar al-Assad after coordinated attacks and ambushes on their forces on Thursday.

The attacks spiralled into a cycle of revenge killings when thousands of armed supporters of Syria's new leaders from across the country descended to the coastal areas to support beleaguered forces of the new administration.