KARBALA, Iraq, Wednesday, May 12 — The American military attacked a mosque in this holy city on Tuesday in its largest assault yet against the forces of the rebel Shiite cleric Moktada al-Sadr, even as the first signs emerged of a peaceful resolution to the five-week-long standoff with him.
The strike on the Mukhaiyam Mosque brought hundreds of American soldiers to within a third of a mile of two of the holiest sites in Shiite Islam, the shrines of the martyrs Hussein and Abbas. A building behind the mosque was fired on, detonating a huge weapons cache, and soldiers stormed the mosque, chasing insurgents out into a hotel and alley.
By 3:30 a.m. Wednesday, some 30 insurgents had taken up positions around the Shrine of Abbas, and they appeared to be lobbing mortars from that area at the Mukhaiyam Mosque. Special Forces soldiers began organizing groups of Iraqi forces to counterattack. Fighting was still intense five hours later. Casualties could not be immediately determined.
Until now, American forces had kept out of Karbala and nearby Najaf, another holy city, fearing to further inflame Iraqi fury against the occupying forces, now fevered because of widely distributed photographs of American personnel abusing Iraqi prisoners.
But before the attack, Col. Peter Mansoor, commander of the First Brigade of the First Armored Division, said military officers had met with Karbala's leaders and believed they would support the operation because they want Mr. Sadr's Mahdi Army run out of town. American forces may be banking on the belief that Mr. Sadr is loathed by the country's mainstream Shiite leaders and that many Muslims disagree with his use of mosques as essentially military bases. On Tuesday, several hundred Iraqis marched in Najaf to demand that he and his militia leave.
The mosque attack came as news emerged that Adnan al-Zorfi, the American-appointed governor in Najaf, had offered to delay attempts to capture Mr. Sadr if he agreed to disband his militia.
The offer, Mr. Zorfi said, was made after extensive consultations with American authorities, suggesting that American leaders are reconsidering their stated goal of "killing or capturing" Mr. Sadr.
In leaflets handed out by his office in Najaf on Tuesday, Mr. Sadr appeared to respond favorably, saying he would end his rebellion if the "occupation forces" agreed to enter talks overseen by Shiite leaders.
"I am ready to end everything if the occupation forces officially ask for negotiations, on the condition that these negotiations are just and transparent and under the stewardship of the Shiite religious authorities," the leaflets said. The leaflets bore Mr. Sadr's signature.
Mr. Sadr, a 31-year-old cleric who commands a large following in Iraq's poor urban neighborhoods, called last month for an uprising to expel the American forces. His men seized government offices in provincial capitals across southern Iraq, but they melted away in most of those places as American troops began to mobilize.
But they have been suffering heavy losses at the hands of the American troops.
Early Monday morning, American forces destroyed Mr. Sadr's headquarters in Baghdad with fire from armored vehicles and possibly helicopters. The military has said it has killed 36 insurgents in the last several days in clashes in Sadr City, a slum of 2.2 million people in northeastern Baghdad. But supporters of Mr. Sadr have begun rebuilding the cleric's headquarters, hauling bricks and concrete blocks to the site.
In the last week, the American forces attacked repeatedly in the area of Karbala, partly in preparation for the mosque attack.
On Monday night, American commanders said they had killed 13 of Mr. Sadr's militiamen in a gun battle in Kufa, which abuts Karbala. They sent a huge convoy on a night assault down the main street of the Mukhaiyam neighborhood a week ago, and have been killing insurgents there with wave after wave of patrols ever since. The Americans also detonated a major weapons cache in an amusement park last Thursday.
Earlier this week, American forces seized the governor's office in Najaf and installed Mr. Zorfi as the new governor.
In an interview on Tuesday, Mr. Zorfi confirmed that he had offered to delay the prosecution against Mr. Sadr, possibly until after the American occupation ends. He said he made the offer after long discussions with the Coalition Provisional Authority, the civilian wing of the American administration in Iraq.
"This is a personal offer made by me, and I have discussed it with the C.P.A. in Baghdad," Mr. Zorfi said. "The offer links the delay of any legal prosecution against Moktada with his clear approval to disband the militias, and hand over its weapons, and letting the local police take over the security of the city."
"I have great hopes that if Moktada approves, the Americans would go along with this deal," he said.
American civilian authorities did not offer any comment.
The mosque attack began as soldiers with the First Armored Division and the Polish and Bulgarian armies left Camp Lima, a military base five miles east of Karbala's center and moved in at 11 p.m. into the maze of streets and dusty alleyways around the one-story mosque. Apache attack helicopters and an AC-130H Spectre gunship swooped through the sky, providing air cover.
Members of Mr. Sadr's militia, known as the Mahdi Army, fired rocket-propelled grenades and AK-47's from rooftops and the windows of dun-colored buildings. A military intelligence analyst estimated there were 50 to 70 militiamen barricaded in the mosque and surrounding buildings. The illuminated twin minarets of the Shrine of Hussein could be seen just a third of a mile to the east.
Tracer rounds arced through the sky as a Bradley fighting vehicle crashed through the rear wall of the mosque compound, then backed up and opened fire with a 25-millimeter canon. An attached storage building burst into flames, and then explosions began erupting. The building had clearly been used to store a huge cache of munitions — the explosions shook the earth for well over two hours.
An Iraqi interpreter working with the Americans broadcast an order of surrender over a loudspeaker. Then Special Forces troops, leading Iraqi commandos, moved through the flame and rubble into the mosque, chasing insurgents into an adjacent hotel and alley.
In three hours of fighting, as many as 20 buildings were raided or destroyed, and pillars of thick smoke curled through the air above rows of palm trees.
Soldiers searching the mosque found large piles of land mines, artillery shells and small white pills, which a Special Forces medic identified as opiates, possibly for use as painkillers.
Their search was interrupted by mortar attack from the mosque near the Shrine of Hussein.
Planning the assault was done in the utmost secrecy and was approved at the highest levels of the military here. Special Forces soldiers here did reconnaissance of the area and brought back photos for the planners. Lt. Gen. Ricardo Sanchez, commander of American ground forces in Iraq, was scheduled to fly down from Baghdad on Tuesday afternoon to oversee the final planning, but canceled at the last minute.
"Our purpose in this operation is to defeat the enemy's capability to conduct any operations in Karbala," Lt. Col. Garry R. Bishop said to more than 100 officers during a briefing on the plan of attack.
The assault will ideally result in "the re-establishment of Iraqi security forces in this area as the only legitimate security," he added.
On Tuesday, Maj. Gen. Martin Dempsey, the commander of the First Armored Division, said the recent success of American military operations had opened a "window" for the political process to succeed, if only briefly.
"We are trying to eliminate his militia from the outside in," General Dempsey said. "We are working from the inside too."
In a moment of remarkable candor, General Dempsey said his forces may have missed an opportunity to eliminate Mr. Sadr last year. Though Mr. Sadr routinely denounced the American occupation, was wanted on criminal charges and was thought to be hoarding guns, American officials, until recently, avoided a confrontation with him. General Dempsey said Tuesday that, in retrospect, that was probably a mistake.
"Why didn't we marginalize him sooner?" the general asked. "Because in the course of the year that I've been here, and in the course of seeking advice from as many possible people as we could — religious leaders, political leaders, tribal leader — as you might expect, we received such a wide variety of advice on how to deal with Moktada al-Sadr that it caused us to be a little bit careful."
"Clearly, in the six months between October and April when he instigated this nationwide attack, he was training troops, gaining resources, stockpiling ammunition," General Dempsey said. "And so when I say we missed the opportunity, we probably gave him six months more than we should have."