BASRA, Iraq -- Suicide attackers unleashed car bombings against police buildings in Iraq's biggest Shi'ite city yesterday morning, striking rush-hour crowds and killing at least 68 people, including 16 children burned in their school buses.
The attacks wounded about 200 people and marked a revival of devastating suicide bombings, which had not been seen during this month's battles between US forces and homegrown guerrillas across Iraq.
Basra's governor, Wael Abdul-Latif, a member of the Iraqi Governing Council, attributed the bombings to Al Qaeda, but a US counterterrorism official said it was premature to make such judgments.
In Fallujah, the bloodiest battlefield in April, an agreement aimed at bringing peace to the city ran into trouble yesterday. Insurgents attacked Marines, prompting fighting that killed 20 guerrillas. Marines said most weapons turned in by residents were unusable, undermining a crucial attempt at disarming fighters.
About 350 miles to the south, in Basra, bombers struck at 7 a.m. as the city's main street market, near one of the targeted police stations, was opening. Shoppers were headed to the stalls of vegetables and other goods, and children were en route to school.
The attackers detonated four cars packed with missiles and TNT in front of three police stations and a police academy. An hour later another car bomb went off outside the police academy in Zubair, a largely Sunni town about 9 miles from mainly Shi'ite Basra.
Police found two other car bombs before they were detonated and arrested three men in the vehicles, Abdul-Latif said.
The blast in front of the Saudia police station wrecked and charred vehicles, including school buses taking kindergartners and girls ages 10 to 15 to school.
The bodies of dead children, burned beyond recognition, were pulled from the wreckage. One body, black as carbon but apparently an adult, was taken away in a pickup.
A reporter counted the bodies of 10 kindergartners and six older girls at Basra's Teaching Hospital, where the morgue was full and corpses were left in the halls.
Nine of the dead and 36 of the wounded were police, Abdul-Latif said.
President Bush condemned the suicide attacks in Basra and said it was imperative that the United States stay the course in Iraq and help establish a democracy there.
"The Iraqi people are looking at Americans and saying, 'Are we going to cut and run again?' " Bush told representatives from more than 1,500 Associated Press member newspapers at the cooperative's annual meeting. "And we're not going to cut and run if I'm in the Oval Office."
The last major suicide attack in Iraq also targeted Shi'ites: Suicide bombers detonated explosives strapped to their bodies among thousands of pilgrims at holy shrines in Karbala and Baghdad on March 2. At least 181 people were killed.
US officials said they thought those attacks were planned by Abu Musab al-Zarqawi, a Jordanian linked to Al Qaeda who they say intends a campaign of attacks to spark a civil war between Iraq's Shi'ite Muslim majority and Sunni minority.
But since the start of April, attention has shifted to Iraqi insurgents, with US troops besieging the Sunni stronghold of Fallujah and a radical Shi'ite militia launching a revolt in the south. Those two fronts, plus a flare-up of insurgent violence around Baghdad and across the country, have stretched US forces in Iraq.
Major General Martin Dempsey, commander of the Army's First Armored Division, suggested the bombings were timed to coincide with the relative quiet over the past few days.
"If I were [the attackers], I think I would probably want to stay in the news," he told the AP gathering. "And the way you stay in the news is space [attacks] out, you conduct attacks sequentially, not simultaneously" with other violence.
The blast yesterday was the bloodiest attack in Basra, a city in Iraq's far south that has seen little insurgent violence. Of the roughly 200 wounded, 168 were in critical condition.
The blast outside the Saudia station heavily damaged its facade and left a crater 6 feet deep and 9 feet wide. When British troops in charge of Basra came to help, angry Iraqis blocked their way, accusing the British of not securing the city.
The Iraqi interior minister, Samir Shaker Mahmoud al-Sumeidi, said the Basra attack resembled the March 2 suicide bombings and Feb. 1 bombings in Erbil that killed 109 people.
"Today, we all have lost children who are part of Iraq's future, which the terrorists want to destroy. The Iraqi government . . . confirms its resolution on defeating this cancer which is called resistance," Sumeidi said.
Four British soldiers were wounded in the police academy blasts, two of them seriously, the British Ministry of Defense said.