Iraqi police on Sunday said a suicide bomber has detonated an explosive vest among a group of Shiite Muslim pilgrims in Baghdad, killing at least 30 people and wounding at least 30 more. Police said the bomber blew up a short distance from the shrine of Imam Mousa al-Kazim, one of the holiest men in Shiite Islam. Police said a number of Iranian pilgrims are among the casualties. The attack on Sunday came as Shiites prepare to mark Ashura, which falls on the 10th of Muharram under the Islamic lunar calendar - or Jan. 7. It is one of the most important holy days for Shiites and marks the death of Islam's Prophet Muhammad's grandson Imam Hussein.