A suicide bomber detonated a belt of explosives on his body near a highly revered Shia shrine in Najaf on Thursday, killing at least 30 people and injuring 60, officials witnesses said.
The bomber blew himself up while being patted down by policemen near the Imam Ali mosque in the old part of the holy city of Najaf, said Dr Munthir al-Ithari, the head of Najaf's health directorate.
Witnesses and officials had earlier reported two bombs explosions. Al-Ithari said a second bomb did go off, but in a different part of the town. It was not clear if there were any casualties there.
He said 30 deaths and 60 injuries have been recorded so far, and the toll is likely to go up. Among the dead are 22 men including five policemen.
The bombing occurred at about 10.30 am in a market -packed with pilgrims and shoppers - in front of the Imam Ali mosque, which contains the tomb of Prophet Muhammad's son-in-law, Ali.
It is one of the world's most sacred shrines for Shias, the minority sect of Islam.
Najaf, 160 kms south of Baghdad, is a major pilgrim destination for Shias around the world, especially from predominantly Shia Iran. Iran and Iraq are the biggest Shia-majority countries in the world.
Four Iranians were among the injured, al-Ithari said.
Najaf and its twin city of Kufa, a stronghold of radical anti-American cleric Muqtada al-Sadr, are tightly controlled by Shia guards and police to prevent attacks by Sunnis