A fourth day of fighting took place on 6 January between Islamic State of Iraq and the Levant (ISIL) forces and other Syrian rebel factions across northern Syria.

Intermittent in-fighting has occurred in the past between Syria’s Sunni rebel factions, most often sparked by incidents like one faction killing a fighter from another faction at a checkpoint. However, January’s fighting represents the largest and most unified attack on any single faction so far by other rebel factions. Forces from the Islamic State of Iraq and the Levant (ISIL) have since 2 January been resisting attempts to take territory from them by a number of other groups, including Liwa al-Tawhid, Ahrar al-Sham, Jaish al-Mujahideen, Jaish al-Islam and Jabhat al-Akrad, in Aleppo, Idlib, and Raqqa provinces in northern Syria. Areas where ISIL has been ousted include the strategically important Bab al-Hawa crossing into Turkey and the provincial capital of Raqqa. Since fighting broke out, ISIL has also used suicide vehicle-borne improvised explosive devices (SVBIEDs) to target rival factions.

Most, although not all, of the factions currently fighting ISIL belong to the Islamic Front rebel coalition, formed on 22 November 2013. This coalition is estimated to command around 45,000 fighters, and is now probably the most unified and credible rebel coalition on the ground in Syria. It declared war on ISIL following ISIL’s refusal to hand over fighters suspected of killing a doctor affiliated with Ahrar al-Sham, one of the most powerful factions in the Islamic Front coalition. The Islamic Front coalition contains Salafist rebel groups but is less hardline than ISIL, whose allegiance is to Al-Qaeda and to the concept of a global Islamic caliphate. This transnational allegiance and focus is another reason why some Syrian rebels are particularly prepared to fight ISIL, which they suspect of having an international agenda that is not necessarily in line with Syrians’ interests.