Iraqi police say a double suicide bomb attack in a northern district of Baghdad has killed 14 people and wounded 20 others.

Witnesses and officials say the first attacker blew himself up Monday outside an office that provides services for Sunni mosques and shrines in the Adhamiyah district. A second car bomb attack followed shortly afterwards.

Officials said the head of a local U.S.-supported Sunni militia fighting al-Qaida in Iraq was killed during the attack. Most of the victims were members of the Sunni group.

Some Sunni Arabs in Iraq have formed militias called "Awakening Councils" that work with U.S. forces to improve security and fight against al-Qaida-allied groups.

Two other bombings today near universities in Baghdad killed at least four people.

Also, the U.S. military in Iraq says a mechanical failure at the Baiji oil refinery sparked two fires Monday, killing one person and wounding three others. The blaze has been extinguished.

Workers at Iraq's largest refinery, some 250 kilometers north of Baghdad, said at least 10 people were injured in a massive fire.

The discrepancy was not immediately reconciled.