The heaviest fighting in Baghdad came when militiamen from al-Sadr's Al-Mahdi Army attacked police stations and set up checkpoints in the Shiite neighborhood of Sadr City, a heavily populated district in the eastern part of the capital, Kimmitt said.
U.S. troops moved in and secured two police stations in fighting that killed 18 militiamen, Kimmitt said.
In other developments:
A bomb went off Sunday night at a Baghdad hotel used by foreign contractors, ripping through the bar and wounding six British and Nepalese, a hotel employee said.
The bomb struck the Four Seasons Hotel in central Baghdad and tore apart chairs and part of the ceiling in the bar, where the six injured were sitting, the employee said. He said the bomb was placed outside the hotel.
Hotel staff said the six were of British and Nepalese nationality, but did not say how many of each. The extent of their wounds was not known.
Many Nepalese in Iraq serve as security guards for private companies.
Earlier, an explosion tore apart shops in a market in the western Biyaa district. The blast occurred when police tried to dismantle two bombs found in vendors' stalls, witnesses said. Four people were killed and 17 were wounded, the Health Ministry said. Kimmitt said three people were killed.
"Is this the freedom that they want — people cut into pieces?," one man at the market, Fadhil Farid, cried. "What did we do wrong?"
At about the same time, gunmen opened fire on a U.S. patrol in western Baghdad, sparking a firefight that killed three Iraqi police, two civilians and one of the attackers, Kimmitt said. Fighters attacked another patrol in the center of the capital, wounding two Iraqi policemen.
The U.S. foray into Kufa was the deepest move yet into the city, an al-Mahdi Army stronghold. Several tanks pushed as close as 500 yards from Kufa's main mosque, trading fire with militiamen on both sides of the main road, witnesses said. Tanks also moved into the neighborhood on the other side of Kufa, trading fire with fighters.
Two civilians were killed and 10 others - including two children
- were wounded in the battles, hospital officials said. Three houses were destroyed. The tanks pulled out of the city in the afternoon.
"It was the first time the Americans came this far," said Odai Abdulkarim, 24, a mechanic who has a shop off the highway leading to the Kufa mosque, where al-Sadr regularly leads Friday prayers. "We are afraid for our families, afraid the rockets would hit our house."
"Americans don't hit you if you don't hit them," interjected Haidar Abu Zaid, 35, another mechanic. "The al-Mahdi Army fires from our areas, so they have no choice but to fire at them — and we end up getting hurt."
Also Sunday, scattered clashes occurred between U.S. and militia forces in the industrial area of Najaf, where al-Sadr sought refuge last month. Plumes of black smoke could be seen rising from the area.
The U.S. military has vowed to kill or capture al-Sadr and put down his militia, which has taken control of much of the holy cities of Kufa, Najaf and Karbala, south of the capital. But troops have been hampered by the nearby sites revered by Iraq's Shiite majority.
Still, U.S. forces have been moving more aggressively against al-Sadr fighters in their strongholds. U.S. troops raided the cleric's main office in Sadr City on Saturday night, detaining six people — including a suspected al-Sadr lieutenant and financier, Kimmitt said.
Al-Sadr's militia fired mortar shells before dawn Sunday at the governor's office and other British positions in Amarah, 180 miles southeast of Baghdad, the scene of fighting the day before, a British official and residents said.
No British casualties were reported in that attack, but British spokesman Maj. Ian Clooney said "a number of possible mortar positions" were destroyed.
In Basra, 100 miles south of Amarah, three coalition soldiers were wounded when a large explosion occurred near a coalition convoy Sunday morning, Clooney said. Witnesses said the wounded soldiers were British.
Elsewhere, a U.S. soldier was killed and another wounded Saturday in a mortar attack on a coalition base in the northern city of Mosul, the U.S. command said in a statement. Another soldier died in an "electrical accident," the command said.
The latest deaths bring to 765 the number of U.S. service members who have died since the U.S.-led invasion in March 2003. Of those, 557 died as a result of hostile action and 208 died of non-hostile causes.