An audio recording issued by the group also lashed out at the opposition-in-exile National Coalition, saying its members were now “legitimate targets,” according to media reports.
Abu Mohammad al-Adnani called on ISIL militants in Syria to “crush them [the rebels] totally and kill the conspiracy at birth,” warning opposition rebels that “none of you will remain, and we will make of you an example to all those who think of following the same path.”
The defiant stance came after the leader of another Al-Qaeda-linked group, the Nusra Front, urged an end to the clashes in opposition-held territories, warning it threatened to reverse gains made against Syrian government forces.
The rare recording by Abu Mohammad al-Golani, the head of the Nusra Front, underscored the seriousness of the clashes that have pitted a chaotic mix of rebel brigades against ISIL militants.
The Nusra Front has sought to play peacemaker between ISIL and its rivals from the mainstream Free Syrian Army and the extremist Islamic Front, an alliance of seven large militias.
More than 300 people have been reported killed since the clashes erupted Friday, with the figure including several dozen people whose bodies were discovered after they had been executed by ISIL militants.
“The foreigners and supporters will pay the price for losing this great jihadist fighting arena,” Golani said in the recording uploaded to a militant website, referring to non-Syrians and Syrians.
The clashes began in Aleppo and Idlib provinces and has spread to Hama, Homs, and the province of Raqqa, an ISIL stronghold .
The Nusra Front and its rival ISIL are ideologically similar: Both are extreme terrorist groups, loyal to Al-Qaeda.
Tensions simmered against ISIL for months, for detaining foreign reporters, Syrian activists, rival rebel militants and others critical of its rule.
“The mistaken policies of ISIL had a big role to play in igniting this conflict,” Golani said, adding that he and other rebels were trying to form a council to halt the fighting.
The Britain-based Syrian Observatory for Human Rights said that 274 people were killed in the fighting between ISIL and rebel groups through Monday – the figure included 99 ISIL militants and 129 insurgents from the various rebel groups.
Some of the dead perished in car bomb attacks, as ISIL militants used the tactic for the first time against rebel groups, rather than regime targets.
A car bomb attack Monday by ISIL militants in the Idlib village of Rankoush killed 20 militants, the Observatory said.
Meanwhile, at least 34 ISIL fighters – all non-Syrians – have been summarily executed by rebels in the province of Idlib during the offensive, the Observatory said, citing local medical and activists sources.
The most serious fighting Tuesday was in Aleppo and in the extremist group’s chief stronghold of Raqqa, although the Observatory said the fighting spread to the town of Rastan in Homs province, where 15 militants were killed.
The infighting also added more uncertainty to the “Geneva II” peace conference, which is to open Jan. 22 in Switzerland to try to resolve the conflict.
BA/BA