Iraqi firefighters spray water on a car destroyed in a roadside bomb attack near Tayaran Sq. in central Baghdad, Monday, April 14, 2008. The explosion was caused by a roadside bomb targeting a police patrol, missing it and hitting a minibus, killing 4 and wounding 8, police said. (AP Photo/Hadi Mizban)
BAGHDAD (AP) -- A bomb exploded next to a convoy of U.S. military vehicles driving down a commercial street in eastern Baghdad on Monday, setting dozens of stalls in a market ablaze.
The U.S. military said none of the soldiers involved was seriously hurt in the 2 a.m. blast. More than a dozen U.S. and Iraqi firefighting vehicles rushed to the scene to put out the fire, which continued until morning.
A Humvee was damaged in the blast, said an Iraqi police officer who spoke on condition of anonymity because he was not authorized to release the information.
Another bomb placed under a parked car near Tayaran Square in downtown Baghdad killed four people and wounded six Monday morning, police said. The blast missed a police patrol but hit a passing minibus, a police officer said.
The officer also asked not to be identified because he was not authorized to speak to the media.
Monday's explosions were two in a series of attacks on security forces in Baghdad in the past two weeks. Dozens have died in the daily clashes with Shiite militants in the capital's eastern districts.
The U.S. military said militants firing rocket-propelled grenades ambushed an American patrol in eastern Baghdad late Sunday night. Armed helicopters and an Abrams tank repulsed the attack, killing six of the gunmen, the statement said.
The government is demanding that radical cleric Muqtada al-Sadr disband his Mahdi Army militia, which has strongholds in Baghdad's sprawling Sadr City neighborhood, the port city of Basra and other locations in southern Iraq.
Clashes in Basra have abated since a failed government offensive last month to dislodge militia groups. But sporadic violence has been continuing in the country's oil capital.
Late Sunday, unknown gunmen assassinated police Maj. Ali Haider, a commander in the department's serious crimes directorate, said Col. Salim Zaydi.
Haider was a member of the Supreme Islamic Iraqi Council, a Shiite political party that is part of al-Maliki's governing coalition, Zaydi said.
Elsewhere in Iraq, U.S. soldiers discovered a mass grave near Muqdadiyah, about 60 miles north of Baghdad, the military said Monday.
The grave site, which was unearthed Sunday, contained 20 to 30 badly decomposed bodies that appeared to have been buried nearly eight months, according to the statement. It said the remains would be moved to a nearby cemetery.
It was the latest in a series of mass graves discovered as U.S. and Iraqi troops clear former insurgent strongholds amid improved security, allowing stepped up patrols.
Associated Press Writer Bushra Juhi contributed to this report.
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