BEIRUT: Syrian rebels ousted an Al-Qaeda-linked faction from one of its northwestern bastions on Friday, activists said, a significant blow to the group after two weeks of infighting that has undercut the insurgency against President Bashar Assad.
Rebels from Islamists to relatively secular moderates have been fighting the Islamic State of Iraq and Greater Syria (ISIS) faction in the worst internecine violence to break out since Syria's conflict began in 2011.
The fighting since the start of January has killed over 1,000 people, according to Syrian Observatory for Human Rights monitors, and helped Assad's forces claw back territory around the northern commercial hub of Aleppo.
On Friday, the Observatory and activists said ISIS had pulled out of the northern town of Saraqeb, strategically important because it straddles highways connecting Aleppo, the capital Damascus and Assad's coastal stronghold of Latakia.
"They burned their cars before the withdrawal and pulled out after covering fire from a brigade loyal to them," the Britain-based Observatory said.
Rival insurgents - including many from the Islamic Front, a large alliance of some of Syria's most powerful rebel groups - had been fighting to take the town for days and moved tanks and machinegun-mounted pickups against ISIS about a week ago.
A Saraqeb-based activist said ISIS's position weakened when an allied brigade pulled out to protect the nearby town of Sarmin, also under siege by the Islamic Front.
A local commander of the Nusra Front - another al Qaeda-linked group which has clashed with ISIS in some areas - said fighters from Nusra and from the Syrian Revolutionaries Front, yet another grouping in the fractured insurgency, would take over military sites and checkpoints while ISIS and the Islamic Front would withdraw.
"The decision wasn't up to them," the commander said via Skype. "This was a good result. Stopping the clashes is always the best outcome. We in Nusra are not picking any side. We are against the aggressor in each of these incidents and unfortunately both sides are attacking each other."
The claim of an agreement made by the Nusra commander was repeated by the Saraqeb-based activist, but other activists disputed it and it was not immediately possible to verify it independently.
The internal rebel fighting broke out in earnest at the start of January after months of increasing tensions.
Local resentment toward ISIS, a reinvigorated version of al Qaeda in Iraq, had been growing over their kidnapping and killing of opponents and attempts to impose an uncompromising interpretation of Islamic law in territory under their control.
ISIS, which draws strength from a core of battle-hardened foreign Islamists, also angered fellow rebels by seizing territory from rival groups.
But the group's loss of Saraqeb, while significant, is unlikely to bring the fighting much closer to an end.
ISIS still controls large amounts of territory across northeastern Syria including Raqqa, the only major city under full rebel control.
The group has fended off rival advances with a campaign of car bombs and suicide attacks. ISIS detonated four car bombs against its opponents on Thursday alone and at least one on Friday, according to the Observatory.