Nearly 500 people, among them at least 85 civilians, have been killed in a week of fighting pitting Syrian rebels against jihadists in the north of the strife-torn country, a monitoring group said Friday.
The fighting raged as Western governments that back the revolt against President Bashar al-Assad prepared to intensify pressure on the opposition to participate in peace talks with the regime planned for later this month.
A new front opened last Friday in Syria's nearly three-year-old war, when powerful massive rebel groups combined to attack bases and checkpoints of the Islamic State of Iraq and the Levant (ISIL).
While the jihadists were initially welcomed by other rebels, allegations of brutal abuses against civilians as well as rival opposition fighters sparked a backlash, and even accusations that they were serving the interests of the regime.
"We have documented the killing of 482 people in the fighting — 85 civilians, 240 members of the rebel brigades and 157 members of ISIL," said Syrian Observatory for Human Rights director Rami Abdel Rahman.
Among the civilians and rebels killed were 42 hostages who were executed in Aleppo by ISIL.
Rebels also executed 47 ISIL members, mainly in Idlib province in northwestern Syria, Abdel Rahman said.
"The rest of the deaths came during the fighting. It is likely dozens more people have lost their lives, but it is impossible to accurately document all the killings," he added.
He called for "crimes being committed in Syria to be brought before an international court."
Jihadist-rebel fighting has raged mainly in Aleppo, Idlib and Raqa provinces.
On Friday, rebels continued to advance in much of Aleppo and Idlib, where ISIL's presence was relatively weak, while the jihadists had the upper hand in Raqa, which has been under their control for several months.
ISIL has its roots in Al-Qaeda in Iraq, and first appeared in the Syrian conflict in spring last year.
Civilians have suffered massively as a result of the latest fighting, activists say.
"In Aleppo city, people are trapped in their houses, unable to fetch medicine or food for fear they will get shot by snipers if they go outside," said anti-regime activist Alaaeddine.
"In Raqa, the situation is even worse," he added.
Despite the "numerical advantage" enjoyed by Syria's rebels, "ISIL will not be forced out of Syria altogether," according to analyst Charles Lister, a visiting fellow at the Brookings Doha Centre.
"It will maintain operations, but likely in a far more independent manner, and sometimes in opposition to other rebel groups."
ISIL has already carried out several deadly car bombings against rival rebel groups in recent days, particularly in Aleppo and Idlib.
Protesters meanwhile took to the streets Friday, as they have every week since the start of the revolt in March 2011, this time chanting slogans against both Assad and ISIL.
In the northern town of Binnish, protesters chanted: "Syria is free, free! ISIL, get out!" They also held up posters that read: "Bashar al-Assad is our main enemy."
Pressure mounts on opposition
Fierce cross-country fighting pitting rebels against both ISIL jihadists and Assad loyalists came as backers of Syria's opposition upped the pressure on dissidents to attend peace talks slated for January 22.
Speaking to AFP Thursday, veteran opponent and National Coalition member Samir Nashar said: "There are clear signs indicating the Coalition must go to Geneva."
The Coalition will meet on January 17 to decide whether to participate in the so-called Geneva 2 process.
But Syria's main rebel groups have warned opponents against attending the talks and against any negotiation with Assad's regime.
And the main bloc within the Coalition — the Syrian National Council — has said it will withdraw from the group if its general assembly decides to attend the peace meeting.
The pressure from Western governments to join the talks increased as the so-called Friends of Syria prepared for a Sunday meeting in Paris to discuss Syria's transition.
The opposition Coalition meanwhile tried to present itself as the international community's "partner" against terrorism.
"The Coalition calls upon the Friends of Syria group to recognise the important role played by the… (rebel) Free Syrian Army in countering the global threat posed by Al-Qaeda, and the Assad regime's role in supporting extremism," it said.
Syria's civil war has killed more than 130,000 people, and forced millions more to flee their homes.
