Late last week, dozens of FSA fighters were killed in a battle against the ISIS in the northwestern province of Idlib. The FSA battalion chief there was beheaded by the ISIS and his brother slaughtered, the Observatory said.
In the early days of the Syrian uprising, when opponents of the regime were desperate for assistance from any quarter, jihadist fighters were welcomed, but a spate of abuses has fuelled a growing backlash.
Last month, the ISIS was accused of executing a teenager in Aleppo because he committed “blasphemy.”
Anti-alAssad activists in rebel areas are increasingly turning their attention to creating anti-ISIS campaigns.
While the FSA is fighting to overthrow the al-Assad regime, the jihadists are intent on installing an Islamic caliphate in Syria.