At least 46 people were killed and 122 others were injured in an attack by a female suicide bomber in Baghdad.
The attack took place amid a procession by Shia Muslims who were on a pilgrimage to the southern city of Karbala for the religious rite of Arbaeen.
Thousands of worshippers, beating their heads and chests in ritual mourning, pour into Karbala for the rites, many walking for hundreds of kilometers.
Arbaeen is a Shia religious observation, which marks the end of the forty-day mourning period after the Day of Ashoura, the commemoration of the martyrdom of Hussein, the grandson of the Prophet Muhammad.
Thousands of troops and police have been deployed to protect worshippers as they walk towards the Imam Hussein shrine.