The militant group Islamic State of Iraq and the Levant were ousted from Syria's eastern province of Deir Ezzor  on Monday after a hard three-day battle with Islamist rebels, a monitoring group reported.
The Syrian Observatory for Human Rights reported that the jihadist Islamic State of Iraq and the Levant (ISIL) had withdrawn from Deir Ezzor - which borders Iraq - after three days of fighting a coalition of opposition brigades including another Al Qaeda-linked group, the Al Nusra Front , according to Agence France Presse.
ISIL is facing mounting backlash and criticism from rebel brigades who accuse it of abusing and torturing civilians and opposition fighters, AFP added.
Though ISIL was spawned from Al Qaeda's Iraqi branch, the chief of the Sunni militant organization Ayman Al Zawahiri has distanced his Qaeda from ISIL and ordered it to return to Iraq , AFP reported.
ISIL's leader has so far ignored Al Zawahiri's calls and has continued to battle rebels fighting against Syrian President Bashar Assad across opposition strongholds in Syria.
Al Nusra, Syria's Al Qaeda offspring , has not engaged in many clashes with ISIL, but the Britain-based Observatory said that it joined ranks with some 10 other brigades to push the jihadist group out of Deir Ezzor.
According to AFP, the loss of Deir Ezzor  could prove to be be a serious problem for ISIL. The eastern province has oil reserves and is a key conduit for the jihadists to receive arms and manpower from neighboring Iraq.
An Observatory toll reported that at least 1,700 people have been killed in the clashes between rebels and ISIL that began in early January.