BEIRUT:  A fragile cease-fire has begun but scattered violence and clashes continue in Syria.

Members of the Islamic State group have stormed a northern border town that was captured months ago by Kurdish fighters, according to a Syrian rebel official.

Talal Sillo, a spokesman for the predominantly Kurdish Syria Democratic Forces, said Saturday that the IS fighters have attacked the town of Tal Abyad. The fighting began after midnight Friday and was still ongoing, Sillo said. Tal Abyad that has been held by Kurdish fighters since July.

The Britain-based Syrian Observatory for Human Rights also confirmed the fighting in Tal Abyad.

The Aamaq news agency, which is affiliated with the extremist group, reported that IS fighters launched a "surprise attack" on several areas in northern Raqqa province, where Tal Abyad is located. But the report did not provide further details.

Sillo told The Associated Press that SDF fighters "will finish the operation today."