(CNN) — In a blistering new message, the leader of al Qaeda denounces the leader of ISIS as the illegitimate leader of a phony caliphate.
Exposing a glaring hostility between the two jihadi groups, Ayman al-Zawahiri, the leader of al Qaeda, openly attacks ISIS leader Abu Bakr al-Baghdadi for usurping the jihadi movement.
“We do not acknowledge this Caliphate,” he says, according to a translation from SITE Intelligence posted Wednesday. “We do not see Abu Bakr al-Baghdadi as one worthy of the Caliphate.”
He dismisses al-Baghdadi as a pretender who declared himself caliph with the support of only “a few unknown people,” and established ISIS, which calls itself the Islamic State, “by force and with explosions and car bombs,” instead of by “the choice of the people” through “approval and consultation.”
He also faults al-Baghdadi for failing to support Muslims who are not in the Islamic State’s territory.
“When Gaza was burning beneath Israeli bombs, Abu Bakr al-Baghdadi did not support it with one word, but his main concern was that all the mujahideen pledge allegiance to him, after he assigned himself to be the Caliph without consulting them.”
And he accuses al-Baghdadi of sedition, for encouraging al Qaeda followers to abandon their pledges, and instead promise their loyalty to ISIS.
“It’s a major broadside against the Islamic State,” says former State Department counterterrorism adviser William McCants, who is now with the Brookings Institution. “Zawahiri is clearly very angry and frustrated that the Islamic State has been attacking him, attacking his soldiers on the ground, attacking him personally.”
Georgetown University’s Nicholas Palarino says al-Baghdadi is stealing his thunder, and al-Zawahiri feels threatened. “You can compare it to two drug gangs, or two mafia mobs. One is encroaching on the other’s territory.”
The two groups have competing strategies, he says, and right now ISIS is more popular with extremists. “There is a generational split. Zawahiri and al Qaeda are more plotting, planning and patient, whereas Baghdadi is demonstrating results.”
But one U.S. official cautions that it is not necessarily good news for the United States that two of America’s enemies are pitted against each other. Instead, their rivalry may spur them on to outdo one other.
“You have a competition going on that I think is dangerous for the United States,” says Rep. Michael McCaul, chairman of the House Homeland Security Committee. “I worry that they’re going to up the ante.”
It is unclear when the recording was made. But despite his tirade, al-Zawahiri does leave open the possibility of working with ISIS to fight their common enemies.
“Were I in Iraq or in Sham [Syria], I would cooperate with them in fighting the Crusaders,” he says.
But one counter-terrorism official tells CNN that while he would not rule out some cooperation between the groups, the distrust and enmity between the two leaders make unlikely a full reconciliation that could heighten the threat against the United States.