BEIRUT: More than 1,000 people have died in two weeks of fighting between al Qaeda-linked militants in Syria and rival rebels, an activist group said on Thursday, by far the bloodiest internecine violence since the revolt began.
The uprising against President Bashar al-Assad has devolved into civil war after a crackdown on peaceful protests and now pits disparate rebel groups against the government and, increasingly, one another.
The Britain-based Syrian Observatory for Human Rights, a pro-opposition monitoring group, said 1,069 people had been killed in clashes and executions since fighting between the al Qaeda-linked Islamic State of Iraq and Greater Syria (ISIS) and rival rebel forces erupted at the start of this month.
The count included 130 civilians, 21 of them executed by ISIS at the children's hospital that was the group's base in the northern city of Aleppo, the Observatory said.
Another 608 of them were fighters from the Islamist rebel groups and other less ideological rebel groups that have joined forces to confront ISIS.
Fighters from the al Qaeda affiliate accounted for 312 of the dead and the remaining 19 were unidentified, the Observatory said.
An array of rebel groups, including an alliance known as the Islamic Front, which combines some of Syria's most powerful insurgent factions, have been trying to push out ISIS, which also has a presence in Iraq.
ISIL had become increasingly unpopular with Syrians because of its kidnappings and killings of opponents and its drive to impose its own strict interpretation of Islamic law. The group had also provoked the ire of other rebels by capturing territory from rival insurgents.
The fighting has depleted rebel ranks and government forces have retaken territory around Aleppo in its wake, but it has had only limited apparent impact on the overall dynamics of the war, which is largely stalemated.
ISIS fighters have managed to recapture much of the northern province of Raqqa and other parts of Aleppo province which they lost in the initial rebel assault.
The infighting has affected the main regions under rebel control. The central provinces of Homs and Hama have seen some infighting, but the bulk of clashes have been in as the northern and eastern provinces of Aleppo, Raqqa, Idlib and Deir al-Zor.