According to insurgent groups and medics, fighting has raged since Friday between foreign-backed rebels and forces loyal to the al-Qaeda linked Islamic State of Iraq and the Levant.

Violence has raged since foreign-backed militants, attacked checkpoints and bases manned by ISIL, which is accused of horrific abuses against other insurgents, activists and civilians in areas where they operate.

ISIL has also been said to seek hegemony by taking over key roads and checkpoints from the hands of its rivals.

Near Tal Rifaat, a village in the northern province of Aleppo, at least 10 foreign backed militants were killed in an ISIL attack on their vehicles, said the so-called Syrian Observatory for Human Rights.

In the Aleppo town of Hreitan, five other militants were killed Saturday in a car bomb attack by ISIL, the Observatory said, citing insurgent and medical sources on the ground.

In Idlib in the northwest of Syria, which has also seen major infighting, four militants were killed in an ISIL ambush near Jabal al-Zawiya, while five others were executed by ISIL in the town of Harem.

Scores of other militants have been killed or captured by ISIL since Friday, chiefly in Aleppo and Idlib provinces.

On Sunday, fighting shifted to a new province, this time to the town of Tabqa in Raqa on the northern border with Turkey.

In a reflection of the complexities of Syria's war, the militant group of Al-Nusra has been involved in some of the fighting against ISIL in recent days, though both groups have their roots in Al-Qaeda in Iraq.

ISIL has claimed responsibility for a suicide attack killing four people this week in a Hezbollah bastion in southern Beirut.

NJF/NJF