MONROVIA, Liberia (AP) _ U.S. Marines bolstered forces at the American embassy here today as efforts to negotiate a cease-fire stumbled. Thousands of Liberians fled to the port, seeking a way out of Monrovia's chaos.

The number of Marines at the embassy was increased to 290 from 230. Three American warships carrying 2,000 more moved within three miles off shore of the West African capital for the third straight day.

U.S. Ambassador William Milam, U.N. envoy Anthony Nyakyi and leaders of the African peacekeeping army said warlord Roosevelt Johnson agreed to a cease-fire late Thursday.

But by this morning, negotiators had not been able to reach his rival Charles Taylor, who has insisted that Johnson surrender before he stops fighting.

Thousands of civilians, meanwhile, crowded the city's port today, hoping to flee on several commercial ships setting sail for neighboring West African countries.

``There's an old Russian ship that is rotten, in my opinion ... and at least 1,000 people are on board already,'' said Peter Sebok, owner of West Coast Fisheries. He said at least 2,000 other Liberians were trying to get on ships.

Sebok's own fishing boat was heading to the Ivory Coast later today with 60 Liberians.

The standoff between Taylor and Johnson, who faces murder charges in connection with clashes in Monrovia in March, ignited the latest fighting, which began April 6.

``There will be no cease-fire until the situation is arrested,'' Taylor said over his radio station Thursday.

Taylor called on his National Patriotic Front of Liberia and other factions to assault the military training camp where Johnson's fighters are holed up with frightened civilians.

Sporadic gunfire could be heard today around those barracks.

A businessman who spoke on condition of anonymity today told journalists he had seen Taylor's fighters roasting and eating the limbs of their opponents on the beach.

There was no way to confirm the report, but cannibalism has been present throughout Liberia's six-year civil war, with fighters believing the consumption of their rivals' bodies gives them strength and courage.

Dogs could also be seen on the beach today, chewing on corpses dumped on the sand to be washed away by the sea.

Taylor and Johnson fighters clashed again Thursday on the strategically important Johnson Street Bridge. The bridge leads into the capital and is near the Mamba Point diplomatic section and the American Embassy, where heavy fighting Tuesday led U.S. Marines to shoot to death three Liberians firing weapons toward the compound.

Pentagon spokesman Kenneth Bacon said the latest American show of force was to remind faction leaders of the American presence, and to shorten the helicopter time between the ships and the U.S. Embassy.

``We think there is an adequate force there, but we want to be ready to reinforce our Marine detachment if necessary,'' Bacon said in Washington.

The U.S. military has been evacuating foreigners from the embassy in Monrovia since April 10. More than 2,000 people have been airlifted to neighboring countries, and 25 were evacuated Thursday.

The Clinton administration has endorsed plans for a summit on Liberia among West African nations next week in Ghana, and encouraged members of Liberia's governing Council of State, which includes Taylor, to attend.