THE leader of al-Qaeda has attacked Islamic State for "madness” and "exceeding the limits of extremism” as the two terror groups continue to compete for territory and supporters around the world.
Ayman al-Zawahiri, who succeeded Osama bin Laden when he was killed in 2011, criticised IS for killing and "slandering” his own jihadis.
In an audio message, he branded the rival group's members "cowards” and liars with a "thirsty desire for authority”.
"Isis was struck with madness in takfir [declaring other Muslims to be apostates] and exceeded the limits of extremism,” al-Zawahiri (pictured) said.
"They make takfir on the basis of lies, fabrications and even good deeds of obedience...[it is] is political, convenient and opportunistic.”
The extremist, who has had a $30 million bounty on his head since the 9/11 attacks, claimed ISs was "misusing the enthusiasm of the youth”.
His message came as pressure mounted on al-Qaeda's numerous front groups and allies in Syria, with the US-led coalition increasingly turning its firepower on the group while IS continues to lose territory.
American defence officials said more than 20 al-Qaeda militants were killed in north-western Syria in two rounds of strikes in the first week of January.
Al-Zawahiri made a clear pitch to IS defectors in his speech, urging "ones who seek the truth” to join al-Qaeda instead.