Updated

Gunfire and explosions erupted in Liberia (search)'s capital Wednesday even as a new U.N. peace mission took control, with insurgents and government forces opening fire as the top rebel leader tried to make his way into Monrovia.

Associated Press journalists saw three bodies -- two civilians shot in the crossfire, and a rebel killed by civilians outraged at the return to fighting. Defense Minister Daniel Chea put the death toll at five.

The firefight, with AK-47s and grenade-launchers, marked the most serious clash in Monrovia (search) since an interim West African peace force moved into the capital Aug. 4.

The battle, coming one day after the last U.S. forces withdrew from the city, broke out as top rebel leader Sekou Conneh made his first entry into Monrovia in a motorcade to meet with new President Moses Blah (search).

Conneh's entrance set off tensions in the capital, still divided into rebel and government zones despite nearly two months of calm under the peacekeeping forces.

It was unclear what started the battle, in a crowded, heavily commercial eastern neighborhood.

Some witnesses said former government soldiers -- idled by the Aug. 18 peace deal -- became angry when rebel forces blocked an intersection for Conneh's motorcade.

When the soldiers threw stones, rebels opened fire, witnesses said. AP journalists saw rebels pull out AK-47s and grenade launchers that had been stashed in their vehicles, and join the fight.

The gunbattle lasted at least 20 minutes and sent thousands of civilians running in panic.

There was no word of any injury to the rebel leader, or to West African peace force commander Brig. Gen. Festus Okonkwo, who had been escorting the rebel chief.

Angry, shouting crowds surrounded the peacekeepers as gunfire eased. The civilians blamed the peacekeepers for not averting the clash.

"This should (show) reason for the international community to hurry up and send in all the forces" of the peace mission, Chea said. "The best thing that can happen to this country now is to ensure that the guns are taken from fighters."

The fighting made clear the difficulties still facing peacekeepers, deployed to help secure the peace after the Aug. 11 resignation of President Charles Taylor (search), a warlord behind 14 years of conflict.

On Wednesday, soldiers of the 3,500-strong West African peace force moved under auspices of the U.N. mission, trading their camouflage helmets for the blue ones of the United Nations.

The U.N. mission is to move to promised strength of up to 15,000 men by March.

"We were given a job and we have done the job and done it well. We are happy to be part of the new force to take over," Col. Theophilus Tawiah of Ghana, chief of staff of the West African force, said earlier Wednesday, marking the handover.

In Washington, State Department spokesman Richard Boucher welcomed the U.N. force.

"We appreciate the hard work by the U.N. secretary general and his special representative, Jacques Klein, in ensuring that this operation was up and running by October 1st," he said. "We also applaud the leadership of the Economic Community of West African States in their efforts to bring peace to Liberia."

Boucher said the United States will send nine officers to participate directly in the U.N. operation. The U.S. government also has provided $26 million in equipment for the West African troops and will continue to provide medical support and equipment.

U.S. forces also marked the end of a small American deployment -- just over 200 U.S. forces at peak -- in support of the West Africans.

"The mere presence sent a signal to everybody involved," U.S. Lt. Col. Tom Collins said Wednesday, as a three-ship U.S. battle group sailed away after weeks off Liberia.

"Above all, it gave them (Liberians) confidence that the U.S. was there and sent a signal to the warring factions that we were watching them," Collins said.

President Bush, under international pressure, had sent the U.S. warships, a rapid-reaction force and U.S. Marine liaisons to Liberia, a country founded by freed American slaves in the 19th century.