That was followed by a series of bombs targeting Iraqi Sunnis.

At least two people were killed and seven others were wounded in a suicide car bomb attack in western Iraq's Sunni heartland, al-Anbar province, Monday. The day before, a powerful car bomb in a crowded market the nearby town of al-Haditha, killed at least seven people and wounded 20 more.

Al-Ghanemi said Iraqi troops have already found 12 bombs planted along the roads pilgrims use to walk to Karbala. Security forces had detained two men on suspicion of planting the devices, he added.

On Thursday, worshipers will fast and say prayers through the 15th night of the Islamic month of Shaban, when, according to some traditions within Islam, God is more receptive to prayers.