DAMASCUS, June 2 (Xinhua) -- An explosion hit the rebel-held city of Azaz in northern Syria near Turkey on Sunday, activists said.

The explosion was reportedly caused by a car bomb that went off in center of Azaz, said the report, with no details on casualties yet.

Azaz, located in the northern countryside of Aleppo province, is controlled by the Turkey-backed rebels.

On July 19, 2012, rebels against the Syrian government succeeded in capturing Azaz, which is a highly-valued area due to its proximity to the Turkish-Syrian border.

The Islamic State took control of the city in October 2013 but withdrew from it in February 2014, and the Turkey-backed rebels retook it.