Updated

A car bomb blasted through a busy bus station near one of Iraq's holiest shrines Saturday, killing at least 37 people, police and hospital officials said. Other reports put the death toll as high as 56.

Separately, a suicide car bomb killed 10 people on a major bridge in downtown Baghdad — the second attack on a span over the Tigris river this week, police said. The Jadriyah bridge suffered little damage.

The bus station bombing occurred about 200 yards from the Imam Hussein shrine in Karbala, where the grandson of Islam's Prophet Muhammad is buried — one of the most important sites for Shiites.

Dr. Khalid Adnan Obeid, director of Al-Hussein Hospital, Ghalib al-Daamai of the provincial security committee and Rahman Mishawi, spokesman for Karbala police, all said 37 civilians were killed and 168 wounded. Earlier, hospital officials said at least 56 people had been killed.

The wounded were being treated in a makeshift emergency room set up in tents near the blast site. A forest of racks held intravenous bags. Through it, a man guided a wooden cart stacked high with body parts.

The charred body of a child laid motionless on a stretcher.

At least 16 children were among the dead, Brig. Gen. Abdul-Karim Khalaf, spokesman for the Interior Ministry, told reporters. Iranian and Pakistani pilgrims were also among the casualties, said an official at Al-Hussein Hospital, on condition of anonymity because he was not authorized to release the information.

"I want my father. Where is my father?" cried out 11-year-old Sajad Kadhim as he lay on the grounds of the hospital, where doctors were treating his burns.

"All I remember was we were shopping. My father was holding my hand and suddenly there was a big explosion. I don't know where my father is. I want my father," the boy cried.

A 72-year-old woman who called herself Um Hussein ran through the hospital corridors looking for her daughter and six-year-old grandson.

"They were near the bomb. They went to buy something for our lunch," she said, pounding her head in grief. "What did they do to deserve this? To whom should I complain? There is no government to protect us," she moaned.

Hundreds of people swarmed around ambulances, crying out and pounding their chests. Police fired into the air to disperse crowds and clear roads for emergency vehicles, but angry mobs attacked them and set two police vehicles on fire.

Rioters surrounded the Karbala governor's office and demanded his and provincial council members' resignations — blaming them for lax security. Mobs threw stones at the governor's office and set fire to the building.

"This bombing shows a security breach, and we are investigating where the shortcoming was," Khalaf said.

A curfew was imposed in the area, and the city's entrances were sealed off while police and soldiers patrolled the streets.

"The explosion was a huge one. It took place in a crowded area," said Khalid al-Daami, head of the city's security committee. Among the dead were several women and children, he said.

Karbala lies 50 miles south of Baghdad, and is the destination of an annual Shiite pilgrimage. Hundreds of Shiite faithful were killed traveling back and forth to the city during this year's pilgrimage, which took place last month.

In Baghdad, at least 15 people were wounded in the Jadriyah bridge bombing — the second such attack this week on infrastructure connecting the Iraqi capital's two sides.

On Thursday, a suicide truck bomb completely collapsed the al-Sarafiyah bridge in northern Baghdad, killing 11 people and sending cars plummeting into the waters below.

A regular session of Iraq's legislature descended into bickering Saturday, with the parliament speaker shouting for order as lawmakers argued over who to blame for holes in security that allowed a suicide bomber into their cafeteria.

Speaker Mahmoud al-Mashhadani said his office took "full responsibility" for Thursday's security breach, but reminded legislators that some of them have refused to be searched while entering the building. The bombing killed one Sunni lawmaker.

Separately, Khalaf told reporters the bomber was known to members of parliament, and that they identified his body after the explosion. He did not elaborate. Suspicion has fallen on workers in the building, or a member's bodyguard.

Police said four would-be suicide attackers were killed Saturday in the northern city of Kirkuk when one of them detonated his explosives belt prematurely.

All four men were killed but no civilians were hurt, said police Brig. Adil Zain-Alabideen. He said all four were insurgents embarking on an attack mission, but did not elaborate.

Kirkuk lies about 180 miles north of Baghdad.

Also Saturday, gunmen attacked the western Baghdad house of Adnan al-Dulaimi, head of the largest Sunni bloc in Iraq's parliament, police said. Al-Dulaimi was not at home at the time of the attack, and is believed to be in Jordan.

Clashes erupted between his guards and the gunmen, lasting about half an hour. Five guards were wounded, police said.

Al-Dulaimi's group, the Iraqi Accordance Front, has 44 seats in parliament.

Three bodyguards of the deputy minister of industry, Mohammed Abdul Jabar, were injured in a drive-by shooting on his convoy in western Baghdad, police said. The minister was in the convoy but escaped injury.

In other violence, three civilians and a policeman were killed in drive-by shootings in Fallujah and Hillah, about 60 miles south of Baghdad, police said. Two policemen and a civilian died in a roadside bombing south of Baghdad, and another civilian died in a similar bombing in central Baghdad, police said.

A bomb planted in a garbage can missed a passing police patrol in Baghdad's southwestern Baya district Saturday, but injured three electricity workers who were working nearby, police said.

The U.S. military issued a statement saying American troops captured 17 suspected insurgents, including an alleged Al Qaeda in Iraq member, during raids Saturday morning.

Eight suspected insurgents were killed by British forces late Friday west of Basra, Iraq's second-largest city, the British military said in a statement. The suspects had been planting bombs in the path of a British patrol, the statement said.