NAJAF, Iraq -- U.S. forces adopted a new tactic Tuesday in their sixth day of battles in this city south of the capital, sending patrols armed with loudspeakers into the streets to demand that militants loyal to a radical cleric drop their arms and leave Najaf immediately or face death.
The call, broadcast in Arabic from American vehicles, added a psychological component to the U.S. offensive. It came as U.S. helicopter gunships pummeled a multistoried building 400 yards from the gold-domed Imam Ali Shrine with rockets, missiles and 30 mm cannons -- one of the closest strikes yet to what is one of the holiest sites in Shia Islam.
Plumes of thick, black smoke rose from the building, which serves as a hotel for visitors to the shrine. Witnesses said insurgents were firing from inside it and that U.S. forces returned fire.
"We've pretty much just been patrolling and flying helicopters all over the place, and when we see something bad, we blow it up," said U.S. Marine Maj. David Holahan, executive officer of the 1st Battalion, 4th Marines Regiment.
Nearby, Bradley fighting vehicles swept through a huge cemetery, pursuing small pockets of militants hiding in elaborate concrete tombs. Choppers provided support, firing rockets from above, witnesses said.
Sporadic explosions could be heard elsewhere in the city, and Holahan said militants from radical cleric Muqtada al-Sadr's Mahdi Army militia attacked three police stations, two with small arms fire, one with eight mortar rounds.
Despite the violence, Marines said the clashes were much lighter than in recent days -- though few expected it to stay that way. "I think it's the quiet before the storm," Holahan said.
Parts of Najaf were deserted, but residents ventured out into the streets, driving small cars nervously along palm-lined roads as eight-wheeled Marine vehicles moved through town on "show of force" patrols.
Residents stood at the gates of their houses, staring. A few children rode bicycles, waving. One U.S. tank stood guard at an intersection in front of a turquoise mosque.
The U.S. military has estimated that 360 insurgents were killed in Najaf between Thursday, when fighting began, and Sunday night, a figure the militants dispute. Five U.S. troops have been killed, along with about 20 Iraqi officers.
The fighting has plagued other Shiite communities across Iraq.
In Baghdad's Sadr City neighborhood, groups of three to five Mahdi Army militants attacked a district council hall repeatedly with mortars, gunfire and rocket-propelled grenades, clashing with U.S. and Iraqi forces, said U.S. Capt. Brian O'Malley of the 1st Brigade Combat Team.
The Health Ministry said the skirmish killed one person and wounded 18. Other clashes in Baghdad killed a second person and wounded 11 others.
There were no employees there during the attacks, and O'Malley said about 14,000 people "haven't been able to go to work since the fighting started" in Sadr City days ago.
The violence has jeopardized Iraq's oil industry.
But production resumed at Iraq's vast southern oil fields after authorities reached an accord with militant Shiites who had threatened to attack the country's vital export pipelines for crude, an Iraqi oil official told The Associated Press late Tuesday.
Oil markets welcomed the news, with U.S. crude futures falling by 44 cents a barrel in late New York trading.
Iraq's South Oil Co. reversed a decision it made Monday to curtail output as a precaution against possible sabotage by supporters of al-Sadr. The cleric's followers had warned they might attack pipelines in southern Iraq unless the government halted crude exports. Iraq's other export line in the north to Turkey is already out of operation.
The interim government also has been fighting a largely Sunni insurgency, characterized by a campaign of attacks, bombings and shootings that have plagued Iraq since shortly after the United States invaded, toppling Saddam Hussein.
A roadside bomb detonated as a U.S. military vehicle drove on a street in Baghdad on Tuesday, slightly wounding two soldiers, the military said.
Jordan's official Petra news agency reported Tuesday that Jordanian businessman Jamal Sadeq al-Salaymeh was taken hostage in Baghdad on Monday by kidnappers demanding $250,000 in ransom.
But a Lebanese businessman, Antoine Antoun, was freed after about a week in captivity in Iraq, his father said.
The fighting with al-Sadr's militia has shattered a series of delicate truces worked out two months ago that ended the Mahdi Army's first uprising, which erupted in April.
Clashes Tuesday between the Mahdi Army and police in the southern city of Diwaniyah killed three and injured 45.
The Health Ministry also reported four killed and 18 wounded in Basra, and one killed and 18 wounded in Amarah. But Squadron Leader Spike Wilson, a British military official, said there were no reports of fighting in Basra or Amarah.
Much of the fighting in Najaf on Tuesday was centered on the vast cemetery near the Imam Ali Shrine. The U.S. military accused Mahdi Army gunmen of launching attacks from the cemetery and then running to take refuge in the shrine compound.
Najaf Gov. Adnan al-Zarfi has given U.S. forces approval to enter the shrine, a senior U.S. military official said. But such an offensive would almost certainly cause widespread outrage among the nation's Shiite majority and exacerbate the crisis.
At the request of the governor and the police, the U.S. began broadcasting its messages through the streets Tuesday, said U.S. Sgt. Will -- an Army Psychological Operations officer who would give only his first name.
U.S. officers helped write the messages, which were aired to inform residents that U.S. forces were "here to support" Iraq security forces, he said.
One of them said: "We ask residents to cooperate with the Iraqi army and police." Another said: "There will be no truce or negotiations with terrorists."
In other messages, they threatened them with death.
Will was blunt.
"They're not doing anything good for the people of Najaf," he said, speaking of al-Sadr's militias. "If they don't lay down their arms, they're going to die."