DAMASCUS, Oct. 6 (Xinhua) — At least 40 Ankara-backed Syrian rebels were killed in a blast that rocked their position on the Syrian-Turkish border on Thursday, according to pan-Arab al-Mayadeen TV.

The explosion targeted a group of fighters at the Atama border crossing, which is under the control of the Free Syrian Army (FSA),  between Syria and Turkey, according to the report.

The Islamic State (IS) group has claimed responsibility for the bombing, saying a suicide bomber blew up his explosive-laden car at a rebel position inside the border crossing, which is located in the northern countryside of Syria's Idlib province.

An earlier report by the London-based Syrian Observatory for Human Rights said at least 20 Turkish-backed rebels died in the attack.

Opposition activists said the blast targetted a refugee camp near the border crossing in Atama.

On Aug. 14, a blast hit the same crossing at Atama, killing 35 rebels and civilians, and wounding 40 others.