American troops have started pulling out of the peacekeeping mission in Liberia (search), defense officials said Monday.

Two of three ships in a U.S. amphibious assault group left waters off Liberia's shore during the weekend, and the last one is expected to pull out midweek as the United Nations (search) takes over the peacekeeping mission.

The U.S. departure will mark the end of deployment that the Bush administration ordered only hesitantly -- and then limited in time and size -- partly because the armed forces are stretched thin by the global war on terror and the campaign to topple Iraq's Saddam Hussein (search).

The amphibious landing dock USS Carter Hall and amphibious transport dock USS Nashville started moving north in the Atlantic during the weekend and were likely to make a maintenance stop in Europe before heading home, defense officials said Monday.

That leaves the USS Iwo Jima amphibious assault ships off Liberia's shore with some 2,600 sailors and Marines aboard, and about 100 other troops in Liberia, the vast majority providing security for the U.S. Embassy in the capital of Monrovia.

African leaders and others had asked the United States in early summer to send troops to lead a peacekeeping force in the country ravage by years of conflict. But U.S. officials stressed as they debated the mission in June and July that they wanted only minimal involvement. As troops deployed in August, President Bush said they would leave by Oct. 1.

Most of the Americans never set foot on shore. A few hundred were sent for less than two weeks in mid-August to assist in a buildup of West African peacekeepers and to serve as a backup in case of problems. A few others moved back and forth between the ships and shore to assist in recent weeks.

Separately, an unusually high number of U.S. Marines and sailors -- more than 50 of the 225 who went ashore -- were hospitalized with symptoms of malaria. All but one have returned to duty and Naval doctors are investigating the illness, which troops don't expect to catch since they are given preventative.

Meanwhile, some 3,250 troops serving in the Nigerian-led West African stabilization force will don blue helmets when the United Nations takes over peacekeeping this week, U.N. officials said Sunday.

The regional troops will be the first of up to 15,000 U.N. soldiers expected in Liberia.

Deployment of the troops from eight West African countries in August helped bring more than two months of fighting to halt in and around the capital, Monrovia. But in the countryside, sporadic clashes continue, making it difficult to deliver much-needed humanitarian aid in those areas.

Rebels have been fighting since 1999 to unseat Liberia's former warlord-president, Charles Taylor (search). Thousands have been killed and hundreds of thousands displaced.

Taylor handed over power to his vice president on Aug. 11 and went into exile in Nigeria under pressure from rebels, regional leaders and the United States. His departure was a condition for the U.S. deployment

A new administration is scheduled to be installed Oct. 14, leading to democratic elections in 2005.