The two-day toll from insurgent attacks rose to 183, reflecting a dramatic upsurge in bloodshed following the Dec. 15 parliamentary elections. Some leading Sunni politicians accuse the Shiite-led government of condoning fraud in the voting.
Iraq's prime minister denounced the violence as an attempt to derail the political process at a time when progress was being made toward including the Sunnis in a new, broad-based government and thereby weakening the Sunni-led insurgency.
But Iraq's largest Shiite party, the Supreme Council for the Islamic Revolution in Iraq, blamed the violence on Sunni Arab groups that fared poorly in the elections. SCIRI warned that Shiite patience was wearing thin, and it accused the U.S.-led coalition forces of restraining the Iraqi army and its police forces.
Thursday's death toll — the largest single-day total since Sept. 29, when 162 died, and one of the bloodiest days in the three-year insurgency — included five American soldiers killed by a roadside bomb while patrolling the Baghdad area, the U.S. military said.
Earlier, Iraqi police Capt. Rahim Slaho said the U.S. convoy was heading for the Shiite holy city of Karbala when it was attacked 15 miles south of the city, and five soldiers were killed.
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In the attack's aftermath, a woman and an infant girl in a bright red jumpsuit lay in a pool of blood, their faces covered by a sheet. Television images showed men ferrying the wounded in pushcarts.
The bomber appeared to have blown himself up about 30 yards from the shrine in a busy pedestrian area surrounded by shops.
In Ramadi, an insurgent stronghold 70 miles west of Baghdad, a U.S. spokesman said dozens were killed when a suicide bomber attacked a line of about 1,000 police recruits. Marine Capt. Jeffrey S. Pool initially put the death toll at about 30, but Mohammed al-Ani, a doctor at Ramadi General Hospital, later said 56 people were killed and 60 injured.
The attack took place at a police screening center. Pool said recruits later got back in line to continue the screening process.
The Karbala bomber detonated a vest stuffed with about 18 pounds of explosives and several hand grenades, al-Taie said. Small steel balls that had been packed into the suicide vest were found at the site, as was one unexploded grenade, he said.
Like many pilgrims, Mohammed Saheb travels to Karbala every Thursday to be at the holy site for Friday prayers.
"I never thought such a crime could happen near this holy site," said Saheb, who had a head injury. "The terrorists spare no place from their ugly deeds. This is a criminal act against faithful pilgrims. The terrorists are targeting the Shiites."
Akram Saleh, a vendor, said he lost consciousness after the explosion.
"I was selling toys near the shrine when I flew into the air because of the explosion," he said from a hospital bed, where he was being treated for burns and bruises.
Karbala's governor, Aqeel al-Khazraji, blamed "takfiris and Saddamists" for the Karbala attack. The takfiri ideology is followed by extremist Sunni Muslims bent on killing anyone they consider an infidel, even fellow Muslims. Al Qaeda in Iraq leader Abu Musab al-Zarqawi is a takfiri, and his group often has targeted Shiites.
SCIRI, a partner in the governing Shiite coalition, said the attacks were part of a plot "to eliminate the Shiites in Iraq."
"These crimes took place after statements and threats of a civil war issued by some Iraq political groups," it said. "Such political groups bear the responsibility for every blood drop that was shed."
It said U.S.-led coalition forces were preventing Iraq's army and police from stopping insurgents, an apparent reference to increased American oversight of Shiite-dominated security forces following widespread charges of abuse — especially of Sunni Arab detainees.
"The multinational forces, and the political entities that declared their support for terrorism, bear the responsibility for the bloodshed that happened in the recent few days. They should know that the patience of our people will not last for a long time," it said.
Karbala has been relatively free of violence since December 2004, when seven people were killed and 31 wounded in an attack. But the deadliest civilian attack in Iraq since the war began happened on March 2, 2004 in Karbala, when coordinated blasts from suicide bombers, mortars and planted explosives exploded near Muslim shrines, killing at least 181 people.