At least 20 Syrian rebels were killed in a blast at a border crossing with Turkey on Thursday, the Syrian Observatory for Human Rights said.
The Britain-based monitoring group said it was unclear what caused the blast at the Atme crossing between Turkey and the northern Syrian province of Idlib, adding that around 20 people had also been wounded.
Turkey’s state-run Anatolia news agency confirmed the blast left 20 people dead at Atme, adding that it took place during a “change of guard” among Syrian rebels in the area.
The IS-linked Amaq news agency reported the blast, saying it was a car bomb, without carrying any formal claim of responsibility.
Rebel fighters have been targeted at the crossing before. The Islamic State group claimed responsibility for a mid-August suicide attack there that killed at least 32.