U.S. Forces Take Heavy Losses As Violence Spreads Across Iraq

The Bulgarian Foreign Ministry said a Bulgarian civilian truck driver was killed when gunmen ambushed a convoy of six trucks south of Nasiriyah.

In Amarah, a Shiite area northeast of Nasiriyah that is under British control, fighting over a 48-hour period between Sadr's followers and British troops left 15 Iraqis dead, the British Defense Ministry said.

The Bulgarian military base in Karbala, one of Iraq's two most sacred Shiite cities, came under heavy grenade and machine-gun fire, but the Bulgarian Defense Ministry said there were no casualties among its troops. It said Sadr's militiamen had taken over public buildings in the city.

The Polish military said gunmen in Karbala firing automatic weapons and grenades had ambushed a patrol of Polish, Bulgarian and U.S. troops. Two Poles and three Bulgarians were wounded, it said.

In Kut, about 100 miles southeast of Baghdad, militiamen attacked an armored personnel carrier, killing a Ukrainian soldier and wounding five, the Ukrainian Defense Ministry said. News agencies quoted militia officials as saying two Iraqis were killed.

The clashes in the south, the most intense since President Saddam Hussein's government fell last April, posed a mounting challenge to the U.S.-led administration in Baghdad. U.S. forces, already stretched thin by an insurgency in Sunni areas north and west of Baghdad -- a region known as the Sunni Triangle -- have delegated authority to allied troops. But for months, those units have often been reluctant to play too assertive a role in a region where security is deteriorating, and some U.S. officials have privately questioned whether they are up to the task.

Since last August, the Mahdi Army has grown as a force in southern Iraq, competing for influence and power with three other militias in the region. Estimates of its numbers range from 3,000 to 10,000, and residents familiar with the group say it is relatively well-coordinated, with a hierarchy that can convey orders from town to town.

The U.S. administration was long divided on how to deal with the militia and its leader, Sadr, a 30-year-old junior cleric and the son of a revered ayatollah believed killed by Hussein's government in 1999. But after intense clashes in Baghdad Sunday, occupation officials have moved to disband it. A warrant was made public Monday for the arrest of Sadr, who is accused of having a hand in the slaying of a cleric from a prominent religious family last April in Najaf.

On Tuesday, Sadr left a mosque in Kufa, a stronghold where he had been for two days, and moved to his office a few miles away in Najaf. In a statement, Sadr said he was ready to die for his principles, and he called on his followers to continue their resistance against what he described as an occupation of infidels.

"America has unsheathed its fangs and its despicable intentions, and the conscientious Iraqi people cannot remain silent at all. They must defend their rights in the ways they see fit," the statement read.

Bremer has termed Sadr an outlaw, and a senior U.S. official on Monday described the uprising as a power grab by a marginalized, isolated cleric. But in the statement, Sadr tried to cast the clashes as a revolt against the occupation. He employed religious imagery, historical allusions and denunciation of the U.S. administration in what appeared to be an attempt to play on disillusionment and anger across Iraq over the pace of reconstruction and a troubled political transition.

While Shiites were long tolerant of the occupation, their mood has shifted markedly in past months as senior leaders -- among them Sadr's rival, Grand Ayatollah Ali Sistani -- have criticized U.S. plans to turn over power.

"If this disobedience means anything, it is that the Iraqi people are not satisfied with the occupation and do not accept subjugation and submission," said the typed statement, which bore the mark of Sadr's office. "But now that the occupiers aggressed against our beloved people, it is no longer possible, and it is not right to be silent and accept this in any way."

In Baghdad, anxiety over the turn of events was matched by unease over dozens of casualties in Baghdad's poor Shiite neighborhoods. In Sadr City, a slum of 2 million named for Sadr's father, hundreds gathered before Sadr's office, waving flags and chanting his name. Two U.S. tanks were parked a few hundred yards away, their barrels trained on the crowds. Residents reported clashes overnight, and an Arabic television station said fighting had renewed Tuesday evening.

U.S. military officials declined to comment.

In Kadhimiya, a Shiite neighborhood that is home to a popular shrine, residents warned against a fiercer U.S. crackdown. Some religious Shiites said the prospect of arresting clerics brought back memories of Hussein's repression of the clergy. They suggested such a tactic could turn the hunt for Sadr into something Iraqis would perceive as a broader move against clergy who still command respect, in part for their opposition to Hussein. Some Shiites wondered why U.S. forces had chosen to confront Sadr now, when the charges against him were months old.

"The most important thing is not to lay hands on things sacred to the heart of the Muslims. You don't touch the clerics or mosques," said Hussein Ali Tukmachi, who runs a sign-painting shop near the shrine. "This creates a very dangerous situation. We really need to cool the situation down. Everyone has to control themselves and be wise."

Correspondents Pamela Constable in Fallujah and Karl Vick and Sewell Chan in Baghdad, staff writers Bradley Graham in Washington and Dana Milbank in El Dorado, Ark., and special correspondent Saad Sarhan in Najaf contributed to this report.