BBC: At least 41 people have been killed and 106 injured by a female suicide bomber in north-east Baghdad, an interior ministry spokesman has said.
The woman detonated an explosives vest among a group of pilgrims making the journey to Karbala, 80km from Baghdad. A witness described seeing a fireball.
The Shia pilgrims were marking Arbaeen, the end of 40 days of mourning for the death of Prophet Muhammad's grandson.
Troops and police are on alert during the pilgrimage.
The bomber had hidden the explosives under her abaya - a long, black over-garment, Maj Gen Qassim al-Moussawi told the Associated Press news agency.
Witness Raheem Kadhom said pilgrims were "crying for help" as they lay injured on the ground in the Shaab neighbourhood, AP reported.
Others helped by taking them to hospitals in cars rather than waiting for ambulances, Mr Kadhom said.
Security has also been increased around the revered Imam Hussein shrine in Karbala during the annual festival, which culminates on Friday. Female suicide bomber kills dozens in Iraq >>> | Monday, February 01, 2010