The blasts scattered bodies across the courtyard, destroyed stalls of vendors selling religious texts and ripped turquoise tiles from the walls. The mosque loudspeaker blared a message urging people to donate blood, while police commandos piled charred bodies into pickup trucks. A white blanket covering one body was so soaked with blood that someone tossed a black cloth over it. People sifted through pools of blood and filled handcarts with shoes and body parts. "I was inside, so I fell to the ground," said Nadhum al-Bahadeli, a businessman whose white shirt was splattered with blood across one shoulder, as he helped to clear debris. "Other people were beneath me. When I stood up, I saw lots of dead people scattered across the courtyard, both men and women."

The well-guarded Baratha Mosque is the main religious stronghold of the Supreme Council for the Islamic Revolution in Iraq, an Iranian-backed party that leads Parliament's major Shiite political bloc.

• The attack came as the American ambassador to Iraq, Zalmay Khalilzad, said in an interview with the BBC that if a unified government was not formed soon, a sectarian war could erupt in Iraq and that such a war could engulf the entire Middle East.

Panic erupted then, he said, and worshipers who had been trying to leave streamed back toward the main courtyard. Two other bombers slipped in during the chaos and detonated their explosives near the separate prayer areas for men and women, mosque and security officials said. Sheik Sagheir said some initial reports indicated that at least one of the bombers might have been a man dressed as a woman.

It was clear that the explosions went to the very heart of the Shiites' long-held feeling that they are victims, as had scores of other attacks in the past three years of civil strife. On Thursday, a car bomb exploded just hundreds of yards from the golden-domed Imam Ali mosque in Najaf, killing at least 10 people in what appeared to be an attempt to provoke a bloody cycle of reprisals.