Almost 50 rebel fighters have been killed in three days of skirmishes between jihadists and mainstream rebels in the Syrian city of Aleppo, reports Al Arabiya.

The UK-based Syrian Observatory for Human Rights said on Saturday that the violence began on Thursday between members of the al-Qaeda-linked Islamic State of Iraq and the Levant (ISIL) and a battalion linked to the Arab and Western-backed Free Syrian Army (FSA), both of which are fighting to overthrow Syria’s embattled President Bashar Al-Assad.

“At least 30 fighters from the Ababil Brigade and 14 from ISIL have been killed in combat, and that toll could rise further,” the Observatory’s Rami Abdel Rahman said, according to AFP.

Rahman said that fighting broke out in several district of the city, with ISIL making gains in several areas.

Since July last year, Aleppo’s east district has been held by the rebels, and the west has been held by forces loyal to Assad.

The 13-member Islamic Front for the Liberation of Syria, which split off from the Syrian National Council opposition force, declared the northern commercial hub city of Aleppo to be an independent Islamist state months ago.

Since that time, a second civil war has begun in war-ravaged Syria, between the more moderate rebel groups and the Islamist extremist groups.

Members of Al-Nusra and other Syrian rebels groups have committed atrocities during the Syrian civil war, including publicly beheading a Catholic priest who was accused of collaborating with Bashar Al-Assad’s regime.

Some of the Islamist groups have attempted to soften their image in an attempt to win hearts and minds – holding stand up comedy shows and handing out toys to local children.