U.S. warships off the coast of Liberia are ready to provide logistics and communications assistance to West African troops in Liberia (search), and some American forces probably will go ashore, a senior official said Monday.

The official said there was "certainly the possibility, maybe even a probability" that some Americans will be dispatched to Liberia to cooperate with West African troops being sent to the beleaguered country.

Nigerian troops, numbering fewer than 200, landed on Monday, the first installment of what is expected to be a 3,250-troop deployment. The State Department welcomed the deployment.

In addition to logistics and communications, the U.S. forces also are expected to help out in planning and may provide air transport as well, said the senior official, asking not to be identified.

President Bush has said Liberian President Charles Taylor (search) must go and a cease-fire must be in place before U.S. troops go ashore.

The USS Iwo Jima (search) amphibious assault ship and USS Carter Hall (search) amphibious landing dock were in waters off Liberia and were staying out of sight for now. They had not been given orders for any mission, defense officials said Monday.

The ships were expected in the coming days to move into positions where they could be seen from land, to serve as a show of force.

The third ship in the U.S. amphibious group, the transport dock USS Nashville, is moving toward Liberia but was still several days away because the ships were not together when the group was ordered to head for Liberia.

State Department spokesman Philip Reeker said humanitarian assistance cannot arrive quickly in Liberia without the cooperation of government forces and the two rebel factions.

"They must stop fighting and restore and respect the cease-fire," Reeker said. "Liberians should cooperate with international peacekeepers and humanitarian relief workers."

The senior official acknowledged that what the United States is prepared to do is far more limited than what some in the international community were expecting.

U.N. Secretary General Kofi Annan, for example, has been pushing for a 2,000-member U.S. force to intervene directly in Liberia.

Defending the American role, the official pointed out that no Western democracy besides the United States is doing anything to help the Liberians.

There are suspicions here that Taylor has been supported by Libya and the Lebanon-based Hezbollah militants. The official rejected suggestions that Taylor has had links with Al Qaeda.

Libyan leader Moammar Gadhafi (search) was a sponsor of Taylor when the Liberian led a rebel force into the country in 1989, touching off an extended period of warfare. Taylor was elected president in 1997.