London, Sep 11 (IANS): Islamist terror group Al Qaeda has slammed fellow jihadi Islamic State (IS) militants followed by an angry speech by its leader, the media reported on Friday.

Ayman al-Zawahiri, who replaced slain Al Qaeda leader Osama bin Laden four years ago, blasted IS in an audio message, the Mirror online reported.

Al-Zawahiri accused IS chief Abu Bakr al-Baghdadi of sedition for declaring himself the leader of all Muslims - the fourth Caliph.

“We have endured a lot of harm from Abu Bakr al-Baghdadi and his brothers, and we preferred to respond with as little as possible, out of our concern to extinguish the fire of sedition," al-Zawahiri said in the audio message.

“But Abu Bakr al-Baghdadi and his brothers did not leave us a choice, for they have demanded that all the mujahideen reject their confirmed pledges of allegiance, and to pledge allegiance to them for what they claim of a caliphate."

Al-Baghdadi had called on the world’s Muslims to obey him as the head of the caliphate in a rare public speech in Mosul, Iraq last year.

Zawahiri said "everyone was surprised" by al-Baghdadi's declaration and he had done this "without consulting the Muslims".

IS was formerly the Al Qaeda branch in Iraq but split from the larger group two years ago.