Al Qaeda 'declares war' on ISIS as 9/11 terror group boss blasts 'seditious' caliphate 0 comments 09:02, 11 September 2015 Updated 09:49, 11 September 2015 By Jon Dean Ayman al-Zawahiri, who replaced Osama bin Laden as boss of the jihadis four years ago, slammed his opposite number in an audio message AFP/Getty Images Surprised: Baghdadi 'did not consult Muslims' before declaring a caliphate, al-Zawahiri says Terror group al Qaeda has 'declared war' on fellow jihadists Islamic State, it is reported. Ayman al-Zawahiri, who replaced Osama bin Laden as boss of the 9/11 killers four years ago, blasted his opposite number in an audio message. He accused ISIS chief Abu Bakr al-Baghdadi of 'sedition' and said he was not the leader of all Muslims as he claimed. The declaration of war will 'irreconcilably' divide the two militant groups, a counter terrorism expert has said. In the message, released online on Wednesday, he said: "We preferred to respond with as little as possible, out of our concern to extinguish the fire of sedition, 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." "Everyone was surprised" by Baghdadi's declaration anointing himself the fourth caliph in Islamic history, he added. He had done this "without consulting the Muslims," Zawahiri said. Speaking to 6abc, counter terrorism expert Matthew Olsen said: "Zawahiri until now has not been willing to openly condemn Baghdadi and ISIS - it highlights how deep the division is between al Qaeda leadership and ISIS. "It suggests that the differences are irreconcilable. "Had ISIS and al Qaeda realigned by joining forces, it would be terrible." The outburst came just ahead of the 14th anniversary of the September 11 attacks. It is hoped the division could provide an opening for counter-terrorism operatives to exploit. Mr Olsen said misinformation tactics could pit the two jihadi menaces against each other. Divided: Counterterrorists could exploit the friction between the two terror groups In Afghanistan and Pakistan, the ISIS franchise known as IS Khorasan Province "has been fighting non-stop" with the Taliban and al Qaeda, an official said. "Fighting each other makes our job easier," he added. ISIS, formerly the al Qaeda branch in Iraq, split from the larger group two years ago.