Syrian rebels seized an Al Qaeda-controlled compound in northern Syria Sunday, according to the Associated Press.
Activists informed AP that the rebels seized the compound from Al-Qaeda-affiliated Islamic State in Iraq and the Levant (ISIL) in Syria's Manbij.
The Syrian Observatory for Human Rights reported that ISIL used car bombs for the first time to defend the compound, and said that the infighting in Manbij represents some of "the most serious" clashes on record between opposition forces.
Infighting between ISIL and Syrian rebels has increased dramatically over the weekend after Syrian civilians accused the opposition for killing a popular doctor.