Shiite and Sunni clerics from about 80 countries are gathering in Iran's holy city of Qom to develop a strategy to combat extremists including the Islamic State group that has captured large parts of Iraq and Syria.

Ayatollah Nasser Makarem Shirazi, the chief organizer of the conference, appealed for consensus among Islam's two main branches, urging them to expose extremist ideology as absurd and to discredit groups espousing it.

Other speakers at the two-day conference blamed the U.S. and Israel for the creation of IS, saying it was formed to position "Islam against Islam."

IS is widely seen as a threat to Islam because it resorts to barbarism and brutal massacres in the name of the religion.