Al-Qaeda has disavowed the Islamic State of Iraq and the Levant (ISIL), whose members have been locked in deadly clashes with Syrian armed opposition, according to a statement posted on jihadist websites.

Al-Qaeda has disavowed the Islamic State of Iraq and the Levant (ISIL), whose members have been locked in deadly clashes with Syrian armed opposition, according to a statement posted on jihadist websites.

Al-Qaeda chief Ayman al-Zawahiri had already ordered the group in May 2013 to disband and return to Iraq, and announced that another jihadist group, the Al-Nusra Front, was Al-Qaeda's official branch in war-torn Syria.

"Al-Qaeda announces it is not linked to the Islamic State of Iraq and the Levant, as it was not informed of its creation... (and) did not accept it," the group said in a late Sunday statement.

ISIL "is not a branch of Al-Qaeda, has no links to it, and the (Al-Qaeda) group is not responsible for its acts," it added.

Extremists were initially welcomed by some rebels in Syria's conflict, but allegations of brutal abuses against civilians as well as rival opposition fighters has sparked a backlash.

ISIL and other foreign-backed opposition groups (including extremist militants) have been engaged in deadly clashes few months ago.