The rebel infighting underscores the immense security challenges that the international weapons experts face as they work amid the civil war to meet tight deadlines.
In a statement released late Wednesday, six rebel groups urged the two major rebel factions battling each other around the town of Azaz near the border with Turkey to "cease the fire immediately" and resolve their differences before an Islamic court.
The two major factions are al-Qaida's Islamic State in Iraq and the Levant on one side, and the Western-backed Free Syrian Army's Northern Storm Brigade on the other.
The Britain-based Syrian Observatory for Human Rights, which documents the civil war and also the rebel-on-rebel fighting, said those that signed the appeal included the Islamic Army, the Tawheed Brigade and Ahrar al-Sham group — all affiliated with the Western-backed FSA alliance.
To read the full story, click here.