The Islamic State of Iraq and the Levant has wrested control of key parts of the eastern Syrian province of Deir al-Zor, worsening infighting that has handicapped the insurgency against President Bashar al-Assad.
The ISIL, which started as an offshoot of al-Qaeda in Iraq, took neighborhoods of Deir al-Zor city from the Al-Nusra Front, Syria's official al-Qaeda affiliate.
It is worth noting that fighting centers around villages on the outskirts of Deir al-Zor where rebel groups have been fighting each other for control of oilfields and strategic areas.