DAMASCUS: Jihadists battling rebels in northern Syria fought on Thursday to recover lost turf nearly a week after a new front opened in the conflict gripping the country.

The fighting comes a day after the Islamic State of Iraq and the Levant (ISIL) was expelled from Aleppo city by rebels fighting to topple President Bashar al-Assad.

Meanwhile, a massive car bomb blast in the central province of Hama killed at least 18 people, the Syrian Observatory for Human Rights said.

Thursday's violence comes nearly a week after rebels launched an all-out attack on ISIL, and almost three years into a war that broke out after Assad's regime launched a brutal crackdown against dissent.

While jihadists were initially welcomed by rebels battling Assad's forces, ISIL became hated because of its systematic abuses and its bid to dominate areas that had fallen out of regime control.

In a counterattack, ISIL launched car bomb assaults late on Wednesday against opposition checkpoints, the Observatory said.

“At least nine people were killed in a car bomb attack by ISIL on a rebel checkpoint... in Al-Bab town” in Aleppo province, Observatory director Rami Abdel Rahman said.

He said similar attacks took place in Hreitan and Jarabulus in Aleppo province, and in Mayadeen in the eastern province of Deir Ezzor.

The attacks came after rebels overran ISIL's Aleppo headquarters on Wednesday, as claims emerged that the Al Qaeda-inspired group had massacred prisoners there.

Amateur video showed protesters taking to the streets of Aleppo celebrating ISIL's expulsion, waving the green, white, black and red flag of the opposition instead of the jihadists' black and white banner.

In Raqa city, fighting raged near the governorate building, which ISIL has for several months used as its headquarters.

While the rebels in Raqa city appeared to be advancing, ISIL was fighting back in the countryside, especially in the border town of Tal Abyad, from which they were expelled earlier this week.

ISIL is believed to be detaining hundreds of activists, rival rebels and foreigners including journalists at several bases in Raqa province.

In Damascus, a security source said the rebel-jihadist fighting benefited Syria's regime, calling it a settling of scores by nations backing different rebel groups.

In less than a week, hundreds of fighters on both sides and scores of civilians have been killed.

Activists say Raqa has become “a city of ghosts”, with bodies in the streets and people afraid to leave their houses because of the violence.

The fighting has not stopped the main conflict between opposition fighters and the regime.

At least 18 people, among them women and children, were killed in the huge car bombing in Kafat in central Hama province on Thursday, the Observatory said.

Much of the province, including Kafat, is still under regime control, and state television reported the “terrorist” blast, saying 16 people were dead and tens more wounded.

The Observatory said “the number of casualties is likely to rise because several of the wounded are in critical condition”, adding that the blast took place near a school.

Most of the victims were civilians, it added. The majority of Syria's car bombings have been claimed by jihadists.

In Aleppo, loyalist warplanes carried out a new air strike on the rebel-held district of Sheikh Maqsud, but there was no confirmation of any casualties.

A brutal aerial offensive by the regime against Aleppo that started on December 15 has killed hundreds of people, mostly civilians.—AFP