Al-Qaeda leader "Ayman al-Zawahri" called on militant l factions in Syria to stop fighting each other and set up a judicial committee to sort out their differences, according to an audio recording released on Islamist websites.
The small but powerful al Qaeda-linked Islamic State in Iraq and the Levant (ISIL) has been caught up in clashes with other Islamist insurgents in recent weeks, often triggered by disputes over authority and territory.
"Our hearts and the hearts of the Muslim nation, which hangs its hopes on you, have bled for the infighting that has spread between the ranks of those waging jihad for Islam", Zawahri said in the five-minute recording.
He said "we call on all our brothers in all the jihadist groups ... to work towards ending this sedition, which will lead to only God knows what".
The militant groups fighting ISIL Islamists, including the al Qaeda-aligned al-Nusra front , in the worst militant-on-militant violence since Syria's conflict began.
In April, the head of ISIL "Abu Bakr al-Baghdadi" tried to merge ISIL with al-Nusra, front defying orders from Zawahri and causing a rift.
The fighting since the start of January has killed more than 1,000 people, according to opposition observatory.