South of the capital, two separate bicycle bombings in town markets killed at least seven people and wounded dozens.
The resurgence of violence in the impoverished Sadr City area began about 1:30 a.m. when an Iraqi patrol searching for three insurgents came under attack. US forces in the neighborhood joined the battle and reported killing between five and eight of the attackers. Iraqi police said eight were killed.
''I am concerned about the events early this morning, but I do not believe this action reflects a pattern of change leading to more violence," said Colonel Joseph DiSalvo, commander of US forces in east Baghdad.
Sadr's militia, the Mahdi Army, was a repeated problem American forces until a truce was negotiated about a year ago that allowed some US troops to pull out of Sadr City to join the November assault on the insurgent stronghold of Fallujah, west of the capital. Before the truce, Sadr's forces had led unsuccessful but bloody uprisings against coalition forces in Kut and the holy cities of Najaf and Karbala, all south of Baghdad.
With a referendum on Iraq's new constitution less than three weeks away, violence in the poor Shi'ite district could deepen opposition among Sadr's supporters who are bucking mainstream Shi'ite support for the constitution.
Shi'ite unity has been seen as critical for passage of the basic law, which most in the minority Sunni Muslim community oppose.
A statement read to reporters by an official with Sadr's office accused US forces of trying to draw them into a battle ''aimed at destroying Iraqi towns, particularly those in pro-Sadr areas and . . . to prevent al-Sadr followers from voting" in the referendum.
The two bicycle bombs hit marketplaces, the first in Hillah, about 60 miles south of Baghdad, where one person was killed and 48 wounded. The second bomb went off in Musayyib, about 40 miles south of Baghdad. It killed at least six and wounded 17, including the city police chief, according to police Captain Muthanna Khalid Ali.
Police also reported finding at least seven bodies in four separate locations in Baghdad -- six men who had been bound and shot, including one identified as a policeman, and a woman in her 20s who seemed to have been strangled and tortured.
