By Khaled Yacoub Oweis
AMMAN, Jan 6 (Reuters) - Rival Islamist rebel groups clashed in the Syrian city of Raqqa on Monday, residents said, as local fighters tried to drive out a foreign-led al Qaeda affiliate that has also seized towns across the border in Iraq.
Activists opposed to President Bashar al-Assad said dozens of Syrian members of the Islamic State of Iraq and the Levant (ISIL) had switched sides, joining other Sunni Islamist factions which have taken advantage of a local backlash against the ISIL and the foreign al Qaeda jihadists prominent among its leaders.
The battles in Raqqa, a provincial capital on the Euphrates River in Syria's largely desert east, left bodies clad in the black favoured by al Qaeda fighters lying in the streets. They followed similar violence elsewhere in recent days which has seen the ISIL lose fighters and abandon some of its positions.
"The ISIL has split roughly into two groups - locals who are beginning to defect and foreign fighters who seem intent on going on fighting," Abedelrazzaq Shlas, an opposition activist in the province, told Reuters.
The Syrian Network for Human Rights, an opposition monitoring group, said 71 ISIL fighters, 20 rival rebels and 26 civilians had been killed in the fighting to oust the ISIL in Raqqa and various other parts of Syria in the last three days.
The fighting comes as groups in Iraq identifying themselves as ISIL have seized Sunni Muslim towns hundreds of miles away on the Euphrates in Iraq, challenging a Shi'ite-led government in Baghdad which they see as allied, like Assad, to Shi'ite Iran.
In Syria, other Islamist groups have sought to take advantage of resentment among local people at efforts by the ISIL to impose radical interpretations of Islamic law and social practices in areas they control.
Syrian fighters from the Islamist factions Ahrar al-Sham and the Nusra Front, another al Qaeda affiliate, have surrounded the main ISIL base in central Raqqa, activists said.
Speaking by satellite phone from Raqqa, 400 km (250 miles) northeast of Damascus, activist Mohammad Izzedin said he could hear gunfire from many places.
An official from Ahrar al-Sham played down suggestions that many ISIL fighters had pulled out into the countryside. He said ISIL men were still manning roadblocks around Raqqa.
Fighting between the ISIL and its Islamist rivals was also reported in the province of Deir al-Zor near Iraq. Activists said the ISIL had evacuated positions on a main highway there along the Euphrates and had pulled out of a district in the city of Deir al-Zor, the provincial capital.
To the west, near the Turkish border, the ISIL has ceded ground to rival Islamists and the Western-backed Free Syrian Army. Raqqa, the only Syrian provincial capital to fall to rebels, was seized by Islamists from various groups last March.
A video posted on the Internet on Sunday showed several men, identifying themselves as anti-Assad rebels, who said they had been freed from a jail run by the ISIL in Raqqa. Activists said the group had held as many as 50 people who were now free.
Despite its setbacks, ISIL could still regroup and draw its rivals into "a prolonged internal conflict", said the European Council on Foreign Relations, a think-tank.
"(This) would significantly impede their ability to fight the Assad regime, which is clearly already benefiting from the shift in both domestic and international focus", it said. (Editing by Gareth Jones)