At least 40 people were killed when a suicide bomber blew himself up at a Shiite Muslim funeral in a southern Iraqi town Sunday.
The blast brought down the ceiling of the mosque in Mussayab, 40 miles south of the capital, Baghdad. Police said some bodies were still trapped beneath the debris. At least 50 other people were wounded.
Those inside had been mourning the death of a man who was killed a day earlier by militants.
"Until now, we are trying to retrieve bodies from under the debris. Most of the bodies were torn to pieces. Legs and hands were scattered on ground," a policeman at the scene said.
It wasn't immediately clear who was behind the bombing, which is the latest in a spate of attacks targeting both Sunni and Shiite places of worship, particularly during funerals.
Iraq's delicate sectarian balance has come under growing strain from the civil war in neighboring Syria, where mainly Sunni Muslim rebels are fighting to overthrow a leader backed by Shiite Iran.
Both Sunnis and Shiites have crossed into Syria from Iraq to fight on opposite sides of the conflict.
Al Qaeda's Iraqi and Syrian branches merged earlier this year to form the Islamic State of Iraq and the Levant, which has claimed responsibility for attacks on both sides of the border.
Suicide bombings are the hallmark of al-Qaeda.
Several other attacks in recent weeks also suggest that Shiite militias, which have so far largely refrained from retaliating, may once again be resorting to violence.
More than 6,000 people have been killed in acts of violence since the start of the year, according to monitoring group Iraq Body Count.