A car bomb exploded in a crowded vegetable market Friday morning in the already bloodied southern Iraqi city of Hilla, killing 14 people, including women and children, and wounding at least 50 others, a police official said.

The car, a Mercedes-Benz, had been parked near the market overnight, said Capt. Muthanna Ahmed of the Babil provincial police force. Police sealed off the market area, where black funeral banners from an attack earlier in the week still hung outside shops. Blood pooled in the streets.

Meanwhile, the death toll from three coordinated bomb attacks in the northern city of Balad on Thursday night rose to 85, according to Qasim Hazim Qaisi, a physician at the city's main hospital. It was one of the deadliest insurgent attacks on Iraqi civilians since the U.S.-led invasion in 2003.

On Monday, a booby-trapped bicycle exploded in front of an ice-cream parlor and juice bar in the same section of Hilla where Friday's bombing occurred. Five Iraqi civilians were killed and 49 were injured.

Hilla, a city of 600,000 residents about 60 miles south of Baghdad, has been the scene of frequent bombings in the past year. On Feb. 28, insurgents left a car rigged with explosives parked overnight outside a health clinic. It went off the next morning, killing more than 100 people and wounding 200. It was the deadliest single attack on Iraqi civilians since the invasion. The bomb appeared to target people applying for government jobs who had lined up at the clinic for mandatory blood tests.

Insurgents are waging a campaign of suicide bombings, shootings and assassinations to try to topple Iraq's U.S.-backed government. The country's draft constitution, on which Iraqis will vote on Oct. 15, has heightened tensions between the country's Shiite Muslim majority and Sunni Muslim minority.

Both Balad and Hilla are predominantly Shiite cities. Abu Musab Zarqawi, the Jordanian leader of the insurgent group al Qaeda in Iraq, has called for violence against Shiites, and the group asserted responsibility for the Balad bombing on an Internet posting.

In the southern city of Basra, an Iraqi police convoy was ambushed late Thursday, killing four policemen and wounding one, according to the Associated Press.

And in Fallujah, hundreds of demonstrators protested the detention of an Iraqi woman by U.S. Marines. The military had no immediate information about the arrest, but residents of the city said the 24-year-old daughter of a prominent Fallujah lawyer, Taha Mahmood Jumaili, was arrested in a raid on the family's home early Friday morning.

Neighbors said the Marines were looking for Jumaili's son, a member of the Fallujah Shura Council, which commanded insurgent forces battling U.S. troops in November.

The son was not in the house, neighbors said. The daughter, Batoul, and three neighbors were apprehended.

Word spread quickly about the raid, and residents took to the streets to call for Batoul's release. Demonstrators staged a protest outside a mosque, but they were dispersed by Marines firing weapons into the air, witnesses said.

Khalid Hamoud, a prominent Sunni religious leader in Fallujah, said he was insulted by the Americans when he went to try to negotiate for the woman's release.

Loudspeakers in the city's mosques, usually used to call worshipers to prayer, broadcast appeals to residents to begin a campaign of civil disobedience until the woman was released. Banners in the city read, "Baathists used to detain women, and now the Marines are doing the same."

The civil turmoil threatens to disrupt the uneasy peace that has prevailed since November, when U.S. troops fought insurgents who had been controlling the city.

In Balad, the extent of the damage inflicted by Thursday's bombings became apparent at daylight Friday, the Muslim day of prayer.

Onlookers walked past the still smoldering wreckage of the exploded cars. Shops were closed, and relatives of the victims wept over the bodies, which were wrapped in thin blankets. The city smelled like burnt metal and death.

The morgue at the Balad hospital filled up quickly. Zainab Mayeh Rahim, 24, stood near the shrouded corpse of her brother, Ali Mayeh Rahim, who worked at a bakery. She said she blamed the government for not securing the country from such attacks.

Elsewhere in Iraq, a car bomb exploded in Mahawil, about 40 miles south of Baghdad outside the Marine base, Camp Kalsu, killing four Iraqi civilians and injuring 10, Iraqi police said. The attack appeared to target Iraqis who worked at the base, according to Ahmed, the Babil police captain.

There was also a suicide car bombing in Musayyib, 15 miles north of Hilla, killing seven and injuring 12. Five of the dead and seven of the wounded were policemen at the Tunnis Police Center, where the attack occurred, said Lt. Col. Mohammad Sami Mamury, a spokesman for the Musayyib police.

At Friday prayer services, top Shiite and Sunni religious leaders called for an end to the violence.

In Najaf, the Shiite cleric Moqtada Sadr called on Sunnis to denounce threats made by Zarqawi against Shiites. "I appeal to our brothers, the Sunnis," he said. "As you raised the slogan of resisting occupation, raise the slogan of condemnation against the stooges of the occupation, at the forefront of which is Zarqawi, who may not be more than a lie by the occupation or a toy in their hand."

At a Sunni mosque in Baghdad, Ahmad Abdul Ghafoor Sammarae, the head of the government's Sunni endowment office, said the government had to do more to stop the violence.

"I appeal to the whole world and to all officials and responsible people both inside and outside the country to stop the bloodshed in Iraq," he said. "Many of our people now prefer to remain and die at home rather than being kidnapped and then tortured and killed by unknown gangs."

Special correspondents Saad Sarhan in Najaf and Salih Saif Aldin in Balad contributed to this report.

A destroyed vehicle sits at a market where a car bomb exploded in Hilla, a city in southern Iraq that has been the scene of frequent insurgent attacks.