Al-Qaida leader Ayman al-Zawahiri sent out an audio message saying ISIS leader Abu Bakr al-Baghdadi is guilty of "sedition" and must be stopped.
He's declared war on ISIS, Breitbart reported.
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ISIS, which was an offshoot of al-Qaida, has been fighting to wrest control of Afghanistan from Taliban and al-Qaida forces. Meanwhile, al-Baghdadi has declared himself the "caliph" and demanded followers of Islam vow loyalty.
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Al-Zawahiri, who recently swore allegiance to Mullah Akhtar, the new Taliban leader, sees Akhtar's now-deceased predecessor, Mullar Omar, as the true "caliph," however.
In the audio file, al-Zawahiri referred to the battles between ISIS and an al-Qaida group in Syria and 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."
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He called al-Baghdadi's proclamation as a "surprise," absent any consultation with other Muslims.
While military and intelligence agents see potential to exploit the rift between ISIS and al-Qaida to advance democracy, the audio seems to throw a kink in those plans.
Al-Zawahiri also said in the clip his anger with al-Baghdadi could be set aside for common causes.
"We don't recognize this caliphate," he said, Breitbart reported. "[But] despite the big mistakes [of ISIS], if I were in Iraq or Syria I would cooperate with them in killing the Crusaders and secularists and Shiites even though I don't recognize the legitimacy of their state, because the matter is bigger than that."
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ISIS, meanwhile, calls al-Qaida a "drowned entity" in the latest publication of its magazine, Dabiq.