CAIRO (AFP) - The head of Al-Azhar, one of the most prestigious centres of Sunni Islam learning, on Wednesday condemned "barbaric crimes" committed by the Islamic State in Iraq and Syria (ISIS).

Militants of the extremist Sunni Islam group are acting "under the guise of this holy religion and have given themselves the name 'Islamic State' in an attempt to export their false Islam", Sheikh Ahmed al-Tayeb said at an international conference in Cairo on fighting extremism.

"I wonder and ask why this blind division exists that has tainted Arab blood," Sheikh Tayeb said, adding that religious, political and economic factors were behind the emergence of groups such as ISIS. But "some feel that our suffering is also a plot by Israel so it remains the most powerful country in the region, and that possibility can not be excluded", he said.

Sheikh Tayeb called on the US-led coalition that is fighting ISIS "to confront those countries who support terrorism financially and militarily".

"But we should not ignore our own responsibility for the emergence of extremism that has led to the formation of organisations such as Al-Qaeda and other armed groups."

The United States launched its first air strikes against ISIS in Iraq in August, and in late September extended the campaign to IS targets in Syria, joined by aircraft from several Arab allies. On Wednesday, the Pentagon said that Iranian warplanes had also carried out air strikes against ISIS in Iraq, although the foreign ministry in Teheran refused to confirm or deny the information.

The Cairo conference, organised by Al-Azhar, has delegates from several countries including Saudi Arabia, Iran and Morocco taking part.