A 150-strong Marine force withdrew to warships off the Liberian capital's coast on Sunday, ending significant U.S. military deployment on the ground after just 11 days and disappointing many Liberians.

The Marines said American troops would be in better position on the warships to respond to any flare-ups in Liberia (search)'s week-old peace accord, meant to end 14 years of conflict that has claimed more than 150,000 lives.

Liberians, watching U.S. military helicopters whir out of sight in the unannounced departure, spoke fearfully of being deserted.

"They're forsaking us," said 22-year-old Emmanuel Slawon, watching the last U.S. helicopter sortie fly out of Liberia's main airport, dangling a Humvee in a giant sling.

"We wish they'd stay until peace would come," Slawon said. "Their presence here puts fear in our fighters -- it makes them think if they carry on hostilities, they'll be handled by the Americans."

The U.S. warships remain off Liberia, appearing in and out of view off a coast lined with black rocks. The United States has not said when they will pull away.

"Why did they go away?" cried Hawa Adra, a 31-year-year-old refugee, watching in the rain with her 3-month-old daughter, Gift, on her back, as the Americans withdrew.

A West African peace force that arrived about three weeks ago has helped stop fighting in Monrovia (search). The government and two main rebel movements also signed a peace accord made possible by the Aug. 11 resignation and exile of former President Charles Taylor (search), now in Nigeria.

But clashes persist in the countryside -- sending refugees fleeing this weekend several miles from the airport.

U.S. military helicopters flew over that area Sunday, on a patrol requested by West African forces to try to help determine the source of gunfire and artillery explosions on Friday.

Liberian Defense Minister Daniel Chea also claimed fighting persisted Sunday near the Guinea border. It was impossible to verify the allegation. State radio claimed up to 1,000 people were killed but Chea said he knew nothing about that.

President Bush put the rapid-reaction force on the ground Aug. 14, under pressure internationally to intervene to quell bloodletting in Liberia, a nation founded by freed American slaves with U.S. government backing in the 19th century.

CH-46 military helicopters carried the Marines back out of Liberia on Sunday, in driving rain.

"Let's hope they'll have peace in Liberia," said one Marine who didn't give his name, heading for the waiting CH-46, its rotors running.

About 100 U.S. troops remain on the ground -- 70 guarding the U.S. Embassy, and 30 acting as liaisons with West African peacekeepers, Lt. Col. Tom Collins, spokesman for the 26th Marine Expeditionary Unit force, told The Associated Press as he left.

The decision "reflects the situation on the ground here," Collins said. "We're here to support [the West Africans], but we can do it better from the ship," he added.

Some 1,500 Nigerian soldiers, the vanguard of a promised 3,250-member West African-led force, have arrived in Liberia, a nation of 3.2 million people.

The Marines had been charged with backing up West African forces if they came under attack. The team largely had stayed at its airport base, out of sight of most Liberians.

Other signs of U.S. military presence clearly had served to encourage Liberia's people, and serve as a deterrent to combatants.

The first visible evidence to Liberians that American military might was in range came Aug. 11, when three hulking U.S. ships in the battle group Iwo Jima (search) appeared off Monrovia. The mist-blurred sight drew cheers from hundreds lining the beaches of the war-ruined capital.

That first U.S. show of force came hours after Taylor resigned, as demanded by the United States, fellow West African leaders and rebels laying two months of bloody sieges to his capital.

In following days, U.S. forces roaming front-lines and noisy helicopter and warplane forays over the city likewise made clear the world's superpower still was watching.

Bush had stressed repeatedly that the U.S. deployment in Liberia would be small and would end by Oct. 1.

"If they want to leave, they can leave," Col. Theophilus Tawiah of Ghana, chief of staff for the West African force, said Sunday, calling the American support helpful no matter where it comes from.

Asked whether the 11-day ground deployment seemed adequate in length, Tawiah laughed. "You'd have to talk to the Americans about that," he said.

A U.N. peace force is due within months, taking over from the West African mission. The U.N. Security Council has approved the U.N. mission but has not yet set the size.

Liberia's factions have broken all previous accords in 14 years of fighting, although prospects for the latest deal appear greatly improved by Taylor's removal.

West African forces in the 1990s had mixed success quelling fighting, then were repeatedly accused of siding with one faction or the other.

The U.S. military deployment had marked U.S. armed force's first significant humanitarian mission in Africa since Somalia in the early 1990s.