BEIRUT — Syrian rebel groups battled one another Monday for control of a provincial capital, part of a vicious round of score settling targeting an Al Qaeda affiliate that gained stature fighting President Bashar Assad but alienated many by imposing strict Islamic law.
Fighting for control of Raqqah followed several days of heavy clashes in rebel-held territory farther west in which disparate militias advanced against fighters from the Islamic State of Iraq and Syria. In March, Raqqah was the first major Syrian city to fall completely to rebel forces, and it has been one of the main bases of the Islamic State of Iraq and Syria.
The offensive against the militants, which some have declared a "second revolution," is the latest and perhaps fiercest fighting in what has become a civil war within the Syrian civil war: the battle to determine which armed factions hold sway on the ground and, ultimately, who will rule Syria if Assad is overthrown.
The U.S. and its allies, long worried about the growing strength of Islamic militants among the Syrian rebels, may be keen to see a victory by more moderate forces among the rebels, but many of those fighting the Islamic State of Iraq and Syria appear to be far from moderate. And in the short run, at least, the fighting is likely to play into the hands of Assad, who the U.S. insists must go.
Syrian government forces have made gains in recent months against the rebels in several areas, and the president has consistently played up infighting among "terrorist" groups, as the government routinely labels its armed foes.
The image of rebels fighting among themselves has provided a public relations windfall for a government that portrays itself as a bulwark against the kind of sectarian-fueled conflict that has racked neighboring Iraq for a decade.
The Islamic State of Iraq and Syria also has been involved in heavy fighting recently in Iraq, particularly in the cities of Fallouja and Ramadi, which long have been strongholds of conservative Sunni Muslim groups that fought the U.S.-led occupation.
The fighting in Syria comes just weeks before an oft-delayed United Nations-organized peace conference on Syria, now scheduled to start Jan. 22. Many rebel groups dismiss it as futile.
The Islamic State of Iraq and Syria had been increasing its dominance in Raqqah, where residents chafed under its harsh, ultraconservative interpretation of Islamic law. It imprisoned journalists and activists opposed to its rule, subjecting them to frequent beatings and electric shocks, according to a report by Amnesty International last month.
Abu Bakr, a media activist for the Shaam News Network in Raqqah, said via Skype that the fighting was pitting other Islamist groups including Ahrar al Sham, the Islamic Front and Al Nusra Front against the Islamic State of Iraq and Syria. He reported fierce fighting near the main government building.
Activists had also posted YouTube videos showing a jubilant crowd of men who purportedly had just been released from what were described as Islamic State of Iraq and Syria prisons in the town. According to Abu Bakr, the prisoners were freed by Al Nusra Front, a fellow Al Qaeda affiliate and former ally of the Islamic State of Iraq and Syria whose role in the current hostilities has vacillated between mediation and confrontation with the latter.
Reports on Monday said that those freed included news photographer Ben Aygun of the Turkish newspaper Milliyet, and there were hopes that information might emerge on the fate of an Italian Roman Catholic priest, Paolo Dall'Oglio, who disappeared on a peace mission to Raqqah last year.
The Islamic State of Iraq and Syria, which has a large number of foreign fighters in its ranks, has been criticized for its hard-line stance, including cracking down on dissent and detaining and summarily executing opponents. When it overran much of the northern Syrian town of Azaz late last year, some residents initially welcomed its presence as an antidote to the shakedowns and thefts attributed to a previous rebel group. But the Islamic State of Iraq and Syria soon alienated residents with its harsh rule.
Other rebel factions, including some of those now aligned against the Islamic State of Iraq and Syria, have been accused of similar abuses.
The involvement of Al Nusra Front, which is known for its expertise with suicide car bombs, suggests that an internal feud about who holds the true banner of Al Qaeda in Syria's war could be part of the reason for the recent fighting. The U.S. government has declared the group a terrorist organization.
The clashes also marked the resurgence of the Free Syrian Army, or FSA, the Western-backed rebel faction that has been beset by disarray.
The fighting dramatized how much the Syrian uprising has changed since it erupted in March 2011 with boisterous street protests.
The fractured opposition includes hundreds of armed factions. Some are well-armed and funded, benefiting from donations by Persian Gulf countries; others are ragtag local militias. They have often shown an ability to fight together for a certain objective, but have never been able to unify.
What began as a bid to curb the Islamic State of Iraq and Syria in the contested northern regions of the country has been transformed into a broad purge on all fighting fronts, with the group withdrawing from most of its headquarters.
Fighting broke out last week around the western cities of Aleppo and Idlib.
In addition to Raqqah, it now has reached the town of Jarabulus, an important rebel supply corridor a mile and a half from the Turkish-Syrian border, where Islamic State of Iraq and Syria headquarters had been overrun by the Islamic Front, an Islamist coalition that has recently started dominating the opposition landscape.
A defiant message on a Facebook page of the local Islamic State of Iraq and Syria leader in Jarabulus insisted that the group was holding fast, and that claims to the contrary came from "enemies of Allah [who] are fighting us via the media."