BEIRUT: A rebel coalition in Syria dominated by Islamic factions announced a new push to dislodge fighters from a rival, Al-Qaeda-inspired group from the northern province of Aleppo, activists said Wednesday.
The announcement, reported by the Britain-based Syrian Observatory for Human Rights, came as the Al-Qaeda-inspired Islamic State in Iraq and Greater Syria overran much of neighboring Iraq's second-largest city, Mosul.
Details of the extent of the new offensive were not immediately known. But one of the groups in the coalition, the Islamic Front, claimed that its fighters recently captured four villages from the Islamic State and killed 17 of its fighters.
The infighting is part of broader rebel-on-rebel clashes that have raged across opposition-held northern Syria since early January.
The new coalition, called the "Operations Room for the People of the Levant" also includes Kurdish groups in Syria, which traditionally have focused on defending their own ethnic areas from other rebel groups, said Rami Abdurrahman of the Observatory.
The new offensive appears to have begun late Monday, said an Aleppo-based activist who uses the name Abu al-Hassan, when two chief towns controlled by the Islamic State, Manbij and al-Bab, came under attack.
The Al-Qaeda-linked Nusra Front and the Islamic Front attacked the town of Al-Bab from the northwest, while Kurdish fighters attacked from the east, he said.
Some of the rebels who joined the new offensive came from the city of Aleppo, abandoning the fight against President Bahar Assad's forces there, said Al-Hassan. "The rebels were sent away from that front to fight the Islamic State."
One video uploaded on social media networks shows fighters of the new coalition firing weapons from the back of a pickup truck. "We will purge this area from the Islamic State," says one fighter. The video appeared authentic and matched Associated Press reporting of the events.
According to the Observatory, which bases its reports from information from activists on the ground, the rebel infighting has killed some 6,000 people - civilians and fighters - since January.
The Islamic State has strongholds in the northern province of Aleppo and also controls a swath of territory from the northeastern city of Raqqa to the eastern province of Deir Al-Zor, neighboring Iraq.
An activist in Deir Al-Zor said the Islamic State has effectively solidified its control over much of Deir Al-Zor over two months of fighting. The activist, who uses the name Abu Abdullah, said Islamic State fighters had reached the town of Busayra, some 62 miles (101 kilometers) from the Iraqi border.
Fighting in Deir Al-Zor alone has killed 634 since May 1, according to the Observatory. The tally includes 39 civilians, 354 rebel fighters, including many from the Nusra Front, and 241 gunmen from the Islamic State.