Issuing a statement, they urged people to take up arms against the militants, Al-Alam news network reported.
"Anyone who can take weapons ought to fight against the ISIL members and support the security forces (in their operations against the group)," they underlined.
Iraq is currently witnessing a wave of violence unprecedented in recent years.
Most attacks are blamed on the militants of ISIL, a group which is also active in Syria.
Takfiri groups, including the so-called ISIL, are reportedly coming to Iraq from neighboring Syria and Saudi Arabia to undermine security in the country.
Iraqi Prime Minister Nouri al-Maliki has said Saudi Arabia and Qatar are responsible for the security crisis and growing terrorism in his country, denouncing the Al Saud regime as a major supporter of global terrorism.