Reports say a bomb attack claimed by the Islamic State extremist group (IS) near Syria's border with Turkey has killed at least 20 people, most of them rebel fighters.
The Britain-based Syrian Observatory for Human Rights said the attack took place on October 6 at the Atmeh crossing, in Idlib Province, and targeted rebels from Turkey-backed factions that have been battling the IS group.
The IS-run Amaq news agency said a suicide bomber targeted a rebel convoy.
Turkish Deputy Prime Minister Numan Kurtulmus described the attack as a "crime against humanity."
In mid-August, more than 30 rebels were killed in a suicide attack claimed by IS militants at the same border crossing.
Rebel factions are currently battling IS militants with Turkish military support in another border region further to the northeast.
