WASHINGTON — Fighting in northern Syria between Islamists and the most powerful of the al-Qaida affiliates in the country is spreading, with most insurgent-controlled cities now caught up in internecine violence that many analysts say will at least in the short-term weaken efforts to oust Syrian President Bashar al-Assad.
At least 270 people, including nearly 50 civilians, have been killed in the rebel-on-rebel violence in the past few days.
The long-simmering rivalry between rebel brigades affiliated with the Western-backed Free Syrian Army and the jihadist group Islamic State of Iraq and the Levant (ISIL) burst into open warfare recently. The fighting intensified after hardline Islamist brigades that several months ago broke with the FSA, joined forces with Western-backed fighters against ISIL, possibly prompted to do so by financial backers in the Gulf.
On Wednesday, Islamist rebels captured a key ISIL base in the city of Aleppo. An ISIL spokesman vowed to crush the rebels as well as their nominal allies in the FSA.
Adding to the complexity, another and smaller al-Qaida affiliate, Jabhat al-Nusra, which appeared to be trying to stay out of the conflict, has joined the coalition against ISIL - a move that may have long-term consequences for internal al-Qaida politics, analysts say. Also on Wednesday, the head of al-Nusra appealed to all sides for a cease-fire - warning that the rebel-on-rebel fighting is jeopardizing the fight against the Assad government.
Rebels fighting ISIL insist that the al-Qaida-affiliated group which is thought to number at least 15,000 fighters must abandon its attempt to establish a state-with-a-state and that it must either integrate into Syria's other opposition militias or leave Syria.
The current infighting appears to have been triggered by the brutal slaying of Islamist commander and physician Dr. Hussein al-Suleiman, who had been placed in charge of a border crossing with Turkey by the Islamic Front but was seized, tortured and killed by ISIL fighters. Photographs of his mutilated body went viral on rebel social media sites. The Islamic Front demanded his killers be handed over for trial before a Sharia court.
Suleiman's killing came on top of other ISIL operations geared at securing control of lucrative border crossings where those in control of them impose "taxes" on supplies being transported from Turkey and to insist on a share of any weapon consignments.
Resentment towards ISIL has been growing for some time among civilians and other rebels who see the jihadist group as overbearing. Areas it controls – or wrested from other rebel groups – are subject to the jihadists' strict interpretation of Sharia law with executions and imprisonment meted out for even small infractions. The al-Nusra Front partly broke with ISIL over the issue of its harsh treatment of civilians.
ISIL "kept pushing other rebels on the ground and refused almost every proposal for arbitration and compromise," says Aron Lund, an analyst with the Washington, D.C.-based Carnegie Endowment for International Peace. The group's intransigence finally managed to alienate even largely sympathetic Islamist groups, he says.
Lund argues that the impetus behind the dizzying series of Islamist mergers and coalitions that formed in opposition to ISIL came as a result of "a wave of encouragement and pressure from foreign funders such as Saudi Arabia, Qatar and various private Kuwaiti Islamist sponsors."
With the clashes drawing major media attention, one analyst, Aymenn al-Tamimi, a scholar at the Middle East Forum, a U.S.-based think tank, cautioned against portraying Islamist fighters as moderates simply because they are confronting ISIL.
Analyst Joshua Landis, author of the influential Syria Comment blog, highlighted a similar point, arguing that the Islamic Front would appear to be holding the door open to a rapprochement with ISIL. According to Landis, "ISIL's goal of an Islamic state is not substantially different than that of the Islamic Front or the many other militias fighting in Syria."