The small al-Qaeda-linked Islamic State of Iraq and the Levant (ISIL) has been caught up in clashes with other extremists in recent weeks, often triggered by disputes over authority and territory, Reuters reported on Thursday.

"Our hearts and the hearts of the 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 alleged in the five-minute recording.

Meanwhile, Muslim nations and governments observe Al-Qaeda and extremism as one of the biggest threat for Islam and Muslims.

"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," Zawahri claimed.

Reuters was unable independently to confirm the authenticity of the recording, but the voice bore a clear resemblance to that of Zawahri.

A British defense study published last September showed that about 100,000 militants, fragmented into 1,000 groups, were fighting in Syria against the government and people.

According to the study, some 10,000 militants were fighting for groups affiliated with al-Qaeda and the rest fight for different militant groups.

In the past three weeks, infighting among insurgents in Syria has claimed over 1,000 lives.

On Sunday, the ISIL chief, Abu Bakr al-Baghdadi, posted an audio message online, accusing other militant groups of backstabbing.

Baghdadi reached out to other militant groups in Syria to stop infighting and instead focus on fighting the government of Syrian president Bashar al-Assad.

The remarks mark a U-turn in the policy of ISIL, which earlier this month vowed to “crush” rival militants groups and considered members of the Syrian National Coalition and the military command of the Free Syrian Army as “legitimate targets.”

NTJ/NJF