Iraqi officials say 965 Shi'ite pilgrims were killed Wednesday in a stampede on a bridge leading to a Baghdad shrine.
They say more than 450 others were injured and that the death toll could still rise. Officials say panic swept through the crowd after a rumor spread that a suicide bomber was among the hundreds of thousands of pilgrims.
Hundreds of women, children and the elderly were either trampled or shoved to their deaths in the Tigris river below.
Prime Minister Ibrahim al-Jaafari declared three days of mourning. The United States offered its condolences and help to the victims.
Earlier Wednesday, insurgents fired mortars near the shrine, the Khadimiyah mosque, killing seven people. A little-known militant group, Army of the Victorious Community claimed responsibility for the attack in an unverifiable Internet statement.
Elsewhere in Iraq, the U.S. military reports the deaths of two soldiers since Tuesday.