IS sleeper cells launch attack in Syria's Raqqa

DAMASCUS, April 3 (Xinhua) -- Four Islamic State (IS) sleeper cells launched an attack on Wednesday against Kurdish-led forces in Syria's northern province of Raqqa, a war monitor reported.

Two IS members carried out suicide bombings using bomb vests at a command center of the Kurdish-led Syrian Democratic Forces (SDF) in Raqqa.

Two other IS members were killed in clashes at the same spot amid reports of losses among the SDF, according to the Syrian Observatory for Human Rights.

The U.S.-backed SDF recently defeated IS in eastern Syria, which pushed the IS sleeper cells to be reactivated in formerly IS-held areas in Syria, particularly in Raqqa, which was the de facto capital of IS in Syria.