Iraqi officials say a car bomb has hit a major Shi'ite pilgrimage in Baghdad, killing at least 9 people and wounding 15. The attack Saturday came on the last day of commemorations for a revered imam.

Earlier Saturday, a group that monitors militant web sites said the al-Qaida affiliate in Iraq claimed responsibility for a wave of car bombings that killed 72 people and wounded nearly 260 Wednesday at the beginning of the Shi'ite Muslim religious commemoration.

The U.S.-based SITE Intelligence Group said the Islamic State of Iraq posted a statement on militant forums saying it was behind the bombings. SITE said the militant group praised the attacks as the “blessed Wednesday invasion” that dealt a blow to the Iraqi government.

Most of the bombs Wednesday exploded in Baghdad and the southern Iraqi cities of Hilla, Karbala and Haswa – predominantly Shi'ite areas that have been targeted before by Sunni Islamist insurgents. The bombings marked one of the bloodiest days since U.S. troops withdrew from the country.

The attacks came as pilgrims were headed to shrines to mark the eighth century death of revered Shi'ite religious figure Imam Moussa al-Kadhim, a great-grandson of the Prophet Muhammad. The commemorations culminate Saturday.