In the center of the capital yesterday, a bomb exploded on a street as a convoy of sport utility vehicles passed, wounding five Iraqis, US Army Lt. Col. Peter Jones said. It was not clear who was in the cars. US troops sealed off the area after the blast.

In the city of Fallujah, about 35 miles west of Baghdad, seven Marines were wounded, besides the one killed, in clashes Friday, a US spokesman in Baghdad said. Footage from Associated Press Television News showed American troops carrying a comrade in a stretcher shortly after an explosion during combat.

The Marines and guerrillas fought for hours in the alleys of the city, which has resisted American efforts to pacify it since the ouster of Saddam Hussein a year ago.

The 1st Marine Expeditionary Force issued a statement saying it was "conducting offensive operations ... to foster a secure and stable environment for the people." It went on to say that "some have chosen to fight. Having elected their fate, they are being engaged and destroyed."

An AP photographer saw two rebels in civilian clothes firing a mortar and another preparing to fire a rocket-propelled grenade.

A freelance cameraman for ABC television, Burhan Mohammed Mazhour, 34, was shot in the head and killed while filming the clashes. It was unclear who killed him.

"We are trying to confirm all the details surrounding his death and have asked the US military for an investigation," ABC News President David Westin said in a statement from New York.

Witnesses said Mazhour and other journalists were taking cover behind a wall, with the Marines in front and the insurgents behind. After rebels fired a barrage of grenades at the US troops, Mazhour peered around the wall and a bullet struck him in the forehead almost instantly.

Four other Iraqis were killed and six wounded in the fighting, said a doctor at Fallujah hospital, Diyaa al-Jumailee. Witnesses said the dead included a shop owner, a customer and two bystanders.

Local resident Salim Saad said occasional explosions and gunfire were heard from the center of the city until about midnight. The roads were largely deserted as people stayed indoors.

This week, Marines took over authority in Fallujah and surrounding areas from the Army. The city on the banks of the Euphrates River is in the so-called Sunni Triangle, where support for Saddam was strong and rebel attacks on American forces are frequent.

In recent months, American troops have rarely ventured into downtown Fallujah, one of the most dangerous areas in Iraq for the US military.

Earlier Friday, four members of the US-trained Iraqi Civil Defense Corps, or ICDC, also were killed while raiding a hideout near Saddam's hometown of Tikrit with US soldiers, the American military said. Three suspected rebels also died and 21 were captured in the raid.

In the town of Shwan, near the northern city of Kirkuk, four people en route to a wedding died when the vehicles they were riding in struck an anti-tank mine. The explosion injured 12 other people, police said Friday.

Gunmen shot and killed an Iraqi police officer late Friday while he was walking home in Kirkuk, Fhadila Rashid, an official at the city's morgue, said Saturday.