A rash of attacks across Iraq on Thursday claimed at least 130 lives, including five U.S. soldiers who died when their vehicle hit a roadside bomb in Baghdad, as the two-day death toll from insurgent attacks climbed to 183.

Homicide bombers attacked Shiite pilgrims in the south and police recruits in central Iraq as officials tried to sort out the details in forming a coalition government.

The latest spate of violence is the deadliest since before the Dec. 15 elections, which were the subject of mass demonstrations across Iraq, with some Sunnis and Shiites claiming vote fraud.

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.

The Supreme Council for the Islamic Revolution in Iraq, or 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."

Thursday's death toll — the largest single-day total since Sept. 14, when 112 died, and one of the bloodiest days in the three-year insurgency — included the death of 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. It was unclear if this incident, during which the convoy was attacked by an improvised explosive device, is related to the five soldiers killed by a roadside bomb while patrolling in Baghdad.

At least 2,188 members of the U.S. military have died since the war began, according to an Associated Press count.

A homicide blast near the Imam Hussein shrine in central Karbala, 50 miles south of Baghdad, killed 63 people and injured 120, according to Karbala police spokesman Rahman Meshawi.

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, a U.S. spokesman said dozens were killed when a homicide 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 in Ramadi, an insurgent stronghold 70 miles west of Baghdad. Pool said recruits later got back in line to continue the screening process.

In other violence Thursday, a homicide car bomb killed three Iraqi soldiers in Baghdad, Lt. Col. Thamir al-Gharawi said, and gunmen killed three people in separate incidents, police said, raising Thursday's death toll to at least 130.

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.

Many pilgrims travel to Karbala on Thursdays to be at the holy site for Friday prayers. Mohammed Saheb said he travels there every Thursday.

"I never thought that such a crime could happen near this holy site," said Saheb, who sustained 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.

A senior official in the Iraqi Accordance Movement, the main minority Sunni coalition, denounced the violence and called for solidarity among Iraqis to defeat it, but he blamed the government for allowing it to happen.

"This government has not only failed to end violence, but it has become an accomplice in the cycle of violence by adopting sectarian policies and by weakening the state and strengthening militia groups," Izzat al-Shahbandar said.

The SCIRI 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 came in March 2004 in Karbala, when coordinated blasts from homicide bombers, mortars and planted explosives exploded near Muslim shrines, killing at least 181 people.

On Wednesday, a homicide bomber struck a funeral for a Shiite politician's nephew, killing at least 32 mourners, wounding dozens and splattering tombstones with blood. The attack in Muqdadiyah, 60 miles north of Baghdad, bore hallmarks of Islamic extremist groups.

There also were two car bombings in Baghdad and a militant ambush on a convoy of 60 oil tankers heading from Iraq's biggest refinery to the capital.

Politicians said the funeral attack was an attempt to hinder a broad-based government or force the dominant Shiite alliance into further compromises. Shiites were said to be close to a deal on a coalition with Sunni Arabs and Kurds nearly three weeks after parliamentary elections.

U.N. Secretary-General Kofi Annan noted that the "horrendous crime" was the latest in a series of increasingly violent attacks after the Dec. 15 elections, and he called on Iraqis not to undermine the democratic process.

Final results from the elections should be released within two weeks, and they are expected to show the United Iraqi Alliance winning about 130 of parliament's 275 seats. That figure is well short of the 184 needed to form a government.

The year 2005 saw 2,880 terrorist attacks targeting Iraqi security forces and civilians, according to the Interior Ministry. Overall, 7,430 Iraqis were killed.

It was impossible to confirm the accuracy of the numbers because many slayings in Iraq go unreported and there are no other official figures with which to compare them. The United States military does not track civilian deaths.

The Associated Press contributed to this report.