Iraq's Interior Ministry says more than 640 Shi'ite pilgrims have been killed in a stampede that broke out Wednesday near a Shi'ite shrine in Baghdad.
Officials say some 300 others were injured in the stampede that erupted on a Tigris River bridge when panicked pilgrims crushed a railing and plunged into the river after a rumor spread that a suicide bomber was in the crowd.
Earlier, insurgents fired mortar rounds near the shrine, killing at least seven people and wounding 36 others.
Thousands of Shi'ite pilgrims were gathering at Baghdad's Kadhimiya mosque to mark the anniversary of the death of revered Shi'ite Imam, Mousa al-Kadim.
Tensions have been running high between Iraq's main religious and ethnic communities ahead of a national referendum on the country's new constitution that Sunni Arabs strongly oppose.
Information for this report is provided by AP, AFP and Reuters.