BAGHDAD -- Deadly bombings killed at least 13 people in the Baghdad area on Monday as Iraqi officials braced for new violence ahead of a planned withdrawal next week of U.S. troops from major cities and urban areas.
The bombings, nearly all in Shiite areas of the capital, came just two days after the year's deadliest attack - a truck bombing that killed at least 75 people in northern Iraq.
The escalating violence will put to the test the Shiite-dominated government's ability to provide security around the country without the immediate help of the U.S. troops remaining in Iraq.
Starting June 30, most of the 133,000 American troops left here will be housed in large bases outside the capital and other cities - unable to react unless called on for help. The withdrawal is part of an agreement that will see all U.S. troops out of Iraq by the end of 2011.
As the violence intensified, the reclusive Shiite cleric Muqtada al-Sadr called on the Shiite-led government to take whatever steps necessary to protect Iraqis for attacks. But in a statement, the anti-American cleric blamed the violence on the continued presence of U.S. troops in the country and demanded a faster withdrawal.
"The Iraqi people are heading toward a new phase that might lift them out from their suffering," the cleric said in a statement, where he called on his followers to remain peaceful.
Last August, he ordered militiamen loyal to his Mahdi Army to lay down their arms and take up social work. The edict came just after U.S. troops working with Iraqi soldiers routed the militia in its stronghold in Baghdad's Sadr City.
In that Shiite bastion, a roadside bomb exploded next to a bus carrying high school students to their final exams on Monday, killing at least three people and wounding 13, including three of the students, police said. The bomb peppered the bus with shrapnel and blood-soaked textbooks covered the floor of the vehicle.
In the deadliest bombing, police said at least five people were killed and 20 were wounded by a car bomb in the Karradah district of the Iraqi capital, on the east side of the Tigris River. It took place on a road leading to a checkpoint that controls access to a bridge into the Green Zone, which houses the Iraqi government and U.S. Embassy.
Another roadside bomb targeted a police patrol in a commercial area of eastern Baghdad's Ur district, killing three and wounding 25.
In the fourth attack, a man wearing an explosive vest blew himself up at a checkpoint leading to the mayor's offices in Abu Ghraib, a predominantly Sunni district west of Baghdad. The suicide bombing killed two people and wounded another five, police said.
The police officials all spoke on condition of anonymity because they weren't authorized to release the information.
In northern Iraq, rescue crews were searching for at least 12 people still missing in a massive explosion Saturday near the ethnically tense city of Kirkuk that flattened a Shiite mosque and dozens of mud-brick houses around it.
Iraqi police have blamed al-Qaeda in Iraq for the attack, saying it was part of an insurgent campaign to destabilize the country and undermine confidence in the government.
Americans will remain ready to help, as they were in the aftermath of Saturday's bombing, but many Iraqis fear their departure after two years of a steady urban presence will prove deadly.
Another bomb exploded Sunday evening in a cafe in a Shiite enclave in a mainly Sunni area of southern Baghdad, killing at least two civilians and wounding 13, police said.
Associated Press Writer Hamid Ahmed contributed to this report.
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