It was the second major attack against Shiite targets in as many days, CBS News correspondent Kimberly Dozier reports.
The horrific attack at the Buratha mosque, affiliated with the country's main Shiite political party, is likely to further stoke tensions between Shiite and Sunni Muslims. The U.S. ambassador warned that sectarian civil war in Iraq could enflame the entire Middle East.
Police Lt. Col. Falah al-Mohammedawi said the blasts occurred at the Buratha mosque, which is affiliated with the Supreme Council for the Islamic Revolution in Iraq, the main Shiite party.
Jalal Eddin al-Sagheer, the preacher at the mosque and one of the country's leading politicians, said there were three assailants. One came through the women's security checkpoint and blew up first, he said. One raced into the mosque's courtyard and other to his office before detonating themselves, said al-Sagheer, who was not injured.
He accused Sunni politicians and clerics of waging "a campaign of distortions and lies against the Buratha mosque, claiming that it includes Sunni prisoners and mass graves of Sunnis."
"Shiites are the ones who are targeted as part of this dirty sectarian war waged against them as the world watches silently," he told Al-Arabiya television.
The attack occurred as worshippers were leaving at the end of Friday prayers, the main weekly religious service. Earlier Friday, the Interior Ministry cautioned people in Baghdad to avoid crowds near mosques and markets due to a car bomb threat.
Rescuers carried the bodies from the mosque compound on makeshift wooden wheelbarrows and loaded them on the backs of pickup trucks. The Baghdad city council urged Iraqis to donate blood for those wounded.
In other developments:
The Interior Ministry had cautioned Baghdad residents to avoid crowds near mosques and markets due to a car bomb threat.
No group claimed responsibility for either attack, although suspicion fell on Sunni Muslim extremists responsible for numerous bombings against Shiite civilians. The Supreme Council for the Islamic Republic in Iraq, the main Shiite party, said the attacks were part of "a war of annihilation" against Shiites.
Mainstream Sunni Arab politicians condemned the attack, calling on all religious and political leaders to rally together in the interest of national unity.
"Bloodshed is forbidden," Sunni lawmaker Adnan al-Dulaimi told Iraqi television. "I call on all religious figures and politicians to work together to avoid provocative acts of sedition."
The attacks were likely to increase tensions between Sunni and Shiite Muslims, already at a high level following the Feb. 22 blast at a Shiite shrine in Samarra and reprisal killings. That bombing triggered a war of reprisal attacks against Sunni mosques and clerics.
"This explosion is trying to provoke Iraqis to sectarian sedition through bombing the mosques," said Salah Abdul-Razzaq, a Baghdad city council member.