U.S. warplanes on Monday bombed a suspected hideout in the insurgent-held city of Fallujah where associates of the Jordanian militant Abu Musab Zarqawi were meeting, the U.S. military said. The Iraqi Health Ministry reported that 20 people were killed and 39 wounded.

The U.S. military said its forces conducted a precision strike just after 6 a.m.

A hospital official said seven people were killed when an ambulance rushing wounded people from the targeted area was hit by a shell.

Zarqawi, who U.S. authorities say is allied with Osama bin Laden's al Qaeda network, is alleged to have organized car bombings, kidnappings and other attacks against Americans and Iraqis. Many military analysts believe he is holed up in Fallujah, which Sunni insurgents and foreign fighters have controlled since U.S. Marines withdrew at the end of April after a three-week siege.

"Intelligence sources reported the presence of several key Zarqawi operatives who have been responsible for numerous terrorist attacks against Iraqi civilians, Iraq Security Forces and multi-national forces," the U.S. military said in a statement Monday. "Based on analysis of these reports, Iraqi Security Forces and multi-national forces effectively and accurately targeted these terrorists while protecting the lives of innocent civilians."

Monday's strike was the latest against targets in Fallujah that U.S. officials say were used by Zarqawi's network.

Witnesses said U.S. warplanes repeatedly swooped low over Fallujah and bombed the residential Shurta neighborhood. Artillery units deployed on the outskirts of the city also opened fire for several hours.

Adel Khamis, a physician at the Fallujah General Hospital, said the dead included women and children, the Associated Press reported. The driver, a paramedic and five patients inside the ambulance that was hit by the shell were also killed, Hamid Salaman, a hospital official, told the AP.

The latest casualties came one day after at least 80 civilians and insurgents were killed around the country in some of the most intense violence in months.

The Iraqi Health Ministry reported that 17 people were wounded Monday in fighting between insurgents and U.S. forces in the capital.

U.S. forces killed six Iraqis when they opened fire on a village near the town of Hilla, about 60 miles south of Baghdad, the Reuters news agency reported. Abdel Zahra Nasrawi, director of the Musayib Hospital, said seven Iraqis were injured by U.S. artillery shelling in Jarf al-Sakhar, near Hilla.

[The U.S. military said Tuesday that guerrillas attacked a U.S. patrol in Baghdad with a roadside bomb and gunfire, killing two soldiers and wounding three, according to Reuters.]

To the north on Monday, U.S. troops continued to block access to the city of Tall Afar as the provincial governor prepared to install a new mayor and police force there.

U.S. soldiers from the 3rd Brigade, 2nd Infantry Division, accompanied by an Iraqi National Guard battalion, moved into Tall Afar early Sunday morning after launching an offensive last week. U.S. commanders said the goal was to expel 200 to 300 insurgents who had taken control of the local government.

By American accounts, two days of delays in installing a new local administration stemmed from unfinished work in the provincial government to choose a new mayor and put together a 600-man police force for Tall Afar, a city of about 250,000 people located about 60 miles from the Syrian border.

The officers said they hoped the still-unidentified mayor would be installed Tuesday or Wednesday at a castle that serves as Tall Afar's city hall. Brig. Gen. Carter Ham, commander of Task Force Olympia, which is responsible for Tall Afar, and Duraid Kashmoula, governor of Nineveh province, would likely attend the ceremony, the officers said.

"There's basically a power vacuum right now," said Army Capt. Nathan Terra. "That's why we're keeping people out" of the city.

"If we don't," he added, "the bad guys will go right back in and we'll have to do this all over again."

The U.S. actions in Tall Afar are part of a larger strategy to reestablish control over restive areas of Iraq before elections scheduled for January. U.S. officials say that strong local authority and security are crucial for successful elections.

On Monday, U.S. troops pulled back to a forward operating base on the outskirts of Tall Afar and were no longer operating continuously inside the city, Army Maj. Thomas Osteen said. Troops who patrolled Tall Afar described a ghost town that was devoid of traffic and had few people on the streets.

Local officials and the U.S. military estimate that 50,00 to 100,000 residents fled the recent fighting in Tall Afar. Many remain in camps outside the city set up by the Iraqi Red Crescent Society.

There are conflicting reports on the number of casualties from the fighting, in which U.S. ground troops attacked and F-15 and F-16 jets dropped 500- and 2,000-pound bombs on what the U.S. military said were insurgent positions near one of the main roads at Tall Afar's northern boundary.

Task Force Olympia has said 67 insurgents were killed. The provincial branch of the Iraqi Health Ministry said 42 Iraqis have been killed since last Thursday, including an undetermined number of women and children.

Terra acknowledged that there were civilian casualties but said most of the dead were combatants. He said that as many as 104 insurgents were killed.

The fighting has shaken the region's complex political structure. The town, a transit point between the oil center of Mosul and the Syrian border, is populated mostly by ethnic Turkmens, bitter rivals of the Kurds who also reside in Iraq's northern region. The bombing has drawn protests from the Turkish government.

A man inspects damage to his house after U.S. bombing and artillery attacks against a suspected hideout in the insurgent-held city of Fallujah.Seven people were killed when a shell hit an ambulance carrying wounded from a U.S. bomb attack.