A suicide attacker driving a minibus yesterday ploughed into a crowd of Shiite pilgrims in central Iraq, killing 23, in the second deadly assault on devotees this week.

The bomber struck pilgrims walking on foot on the outskirts of the shrine city of Karbala, 110 kilometres south of Baghdad, where Shiites are massing to observe Arbaeen rituals. The attack also left 117 people wounded.

Arbaeen marks 40 days after the Ashura anniversary commemorating the slaying of one of Shiite Islam's most revered figures, Imam Hussein, by the armies of the Sunni caliph Yazid in 680 AD.

A senior health official in Karbala who gave the toll said at least one woman and three children were among the dead. The wounded are being treated at two hospitals in the city.

An interior ministry official, who confirmed the casualty toll, said the bomber detonated an explosives-laden bus.

The victims had been travelling from Hilla in Babil province and were among tens of thousands of Shiites, including many from neighbouring, heading to pay homage at Imam Hussein's shrine in Karbala, one of the holiest places in Shiite Islam.

Worshippers continued to flock into the city yesterday despite the attack, said an AFP correspondent in the city, where tens of thousands of police and soldiers have been deployed to safeguard the ceremonies.

Television pictures showed crowds on roads stretching into the far distance, walking as a sign of piety, and carrying flags adorned with Imam Hussein's image.