KARBALA, Iraq — American-led forces surrounded the headquarters of a militant Shiite leader near one of Islam's most revered shrines Saturday and set up roadblocks to prevent more of his supporters from entering the city center a day after three U.S. soldiers were killed in a brief but violent firefight with his bodyguards.

The battle here between U.S. and Iraqi police and the followers of Ayatollah Mahmoud Hassani claimed the lives of a U.S. military police battalion commander and two other U.S. soldiers and left several Americans wounded. Two Iraqi police officers and a large but undetermined number of Hassani's armed followers also were killed.

Shortly after midday Saturday, a coalition military vehicle rigged with powerful loudspeakers pulled up on a main street a few hundreds yards from Hassani's office and began blaring out a demand that he and his followers lay down their arms.

"Attention! Attention! Attention! You are surrounded, it is useless to fight," the speaker declared in Arabic. "You are close to the holy shrines. You have to respect them and you have to respect the clerics. Stop fighting. No more bloodshed is necessary. There is no need for more victims."

In a tent at a Polish military headquarters a few miles from the scene, the head of coalition military forces in Iraq, U.S. Army Lt. Gen. Ricardo Sanchez, met with local commanders and at least two other Army generals for about an hour, apparently discussing how best to end the standoff. The American officers included the 1st Armored Division's assistant divisional commander, Brig. Gen. Curtis Scaparrotti.

The senior officers' presence underscored the high stakes involved for the United States in ending the standoff without more fighting. Shiites make up a majority of Iraq's population and in general have been supportive of the American occupation, in part because they suffered so during the rule of Saddam Hussein, who is a Sunni Muslim. Any serious erosion of Shiite support could seriously jeopardize America's effectiveness in Iraq.

None of the senior officers was prepared to comment on the operation.

"We can't talk about events that are still going on," said Capt. Vojtek Majeran of the Polish army, which is deployed in the city.

As night fell Saturday, American troops, supported by Humvees, kept the alleys and narrow streets near Hassani's main office closed amid rumors that they might move against the armed fighters that remained inside at some point during the night. Five M-1 Abrams tanks blocked a larger road leading toward the headquarters, and U.S. Army Black Hawk helicopters circled overhead.

The area remained quiet during the day, and some residents speculated that both Hassani and those who survived the clash that ended early Friday might have fled during the predawn hours. Hassani is considered one of the lesser known ayatollahs among Shiites. Accounts of the firefight from police, residents and coalition forces suggested that the U.S. military police unit involved might have been lured into an ambush. A 20-year-old Iraqi police officer caught in the attack, Mohammed Hussein, said they spotted a small group of Hassani followers standing down a narrow street several hours after the 9 p.m. curfew, with weapons clearly visible.

Hussein said as the soldiers moved down the street and ordered the men to give up their weapons, an armed Hassani fighter appeared from the right and ordered the soldiers to throw down their arms. Another witness to the fight, who declined to be identified, said the Military Police commander, Lt. Col. Kim S. Orlando, then drew his pistol but was immediately gunned down.

Within seconds, this witness said, the soldiers and polices were hit, first by sustained small-arms fire from the right, then by a volley of rocket-propelled grenades from the upper levels of buildings on the left.

The MPs and Iraqi police returned fire, killing many of the attackers.

A member of Hassani's group who survived the firefight, 20-year-old Sheik Haider, said Friday that the Americans were the first to fire.

In Baghdad, U.S. military spokesman Lt. Col. George Krivo referred to the attackers as criminal gangs. "Once we get to the bottom of this and figure out what the facts are, we, along with the proper Iraqi authorities, will react," he said.

Karbala Police Capt. Hakim Alwan estimated that the cleric had about 200 fighters in the city. The exact motive for an attack on American forces was unclear, although several Shiite factions, some supported by armed militias, have been jostling for power and influence in the city.

Last week, armed backers of a young, firebrand Shiite cleric, Muqtader Sadr, launched armed attacks on two of the Shiite sect's holiest sites in Karbala — the shrines of the Imam Hussein and his half-brother Abbas. Their goal apparently was to tap into the hefty funds donated there by pilgrims. Both sites are believed to receive millions of dollars each year.

Although Sadr has denounced the American-led military occupation, he has so far stopped short of urging his followers to take up arms against it.

In other developments Saturday:

•  Thousands of U.S. and British troops conducted a series of coordinated raids and sweeps on the Al Faw peninsula in southeast Iraq aimed at disrupting criminal and smuggling activity from the city of Basra to the Persian Gulf, U.S. commanders said. "This is a major operation, larger than what we usually see. It will intensify during the next 48 hours," Krivo said.

Military officials said the troops, including 2,000 Marines and sailors, had seized oil barges, oil boats and other vehicles and had arrested 80 people.

•  American officials and members of the Iraqi Governing Council — appointed by the U.S.-led occupation authorities — did not reach an agreement on Turkey's offer to send 10,000 troops to Iraq, spokesmen said. The council fears that Turkey could use its military presence to interfere in internal affairs, while the U.S. Defense Department sees the deployment as a means to reduce pressure on American troops.

•  U.S. authorities announced plans to reopen the 14 July Bridge in Baghdad this month. The bridge spanning the Tigris River has been closed for security reasons since April because it leads to a major thoroughfare behind Saddam Hussein's former palace, which is now used by the Coalition Provisional Authority. Its closure worsened nightmarish traffic congestion in Baghdad.

•  President Bush, in his weekly radio address, said the coalition and its Iraqi partners had refurbished more than 1,500 schools, and were working with UNESCO to print 5 million textbooks. The coalition, he said, "was working to rebuild Iraq's schools, to get the teachers back to work and to make sure Iraqi children have the supplies they need." Bush added that "in many cases, American soldiers have intervened personally to make sure Iraqi schools get the supplies they need."