AMMAN - Rival Islamist rebel groups fought in the Syrian city of Raqqa on Monday, residents said, as local fighters tried to drive out a foreign-led al-Qaida affiliate which has also seized towns across the border in Iraq.

Activists opposed to President Bashar Assad said dozens of Syrian members of the Islamic State of Iraq and the Levant had changed sides to join other Sunni Islamist factions which have taken advantage of a local backlash against the ISIL and the foreign al-Qaida jihadists prominent among its commanders.

The battles in Raqqa, a provincial capital on the Euphrates river in Syria's largely desert east, left bodies clad in the black favored by al-Qaida fighters lying in the streets. They followed similar violence elsewhere in recent days that have seen the ISIL lose manpower 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 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.

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