Shelling and fierce fighting have resumed in Liberia's capital for a fourth day, as warnings grow of a humanitarian disaster.
Monrovia has been plagued by civil war since 1989
Liberian rebels are clashing with forces loyal to President Charles Taylor in the port area of the Monrovia in what is the third battle for the capital in two months.
Defence Minister Daniel Chea says at least 600 people have been killed in recent clashes, but humanitarian workers have so far confirmed only about 100 deaths.
Troops are ready to leave Nigeria and neighbouring countries for Liberia, correspondents say, but the decision on a peacekeeping force remains in the hands of West African military and political chiefs meeting in Dakar, Senegal.
A spokesman for the rebels, speaking from neighbouring Ghana, said instructions had been given to all its forces to stop fighting.
But the BBC correspondent in Monrovia says a similar call from the group's external leadership two days ago went unheeded by its forces on the ground.
United Nations Secretary General Kofi Annan has urged regional nations and the United States to take decisive action to stem the bloodshed which has engulfed Liberia since a peace process broke down earlier this month.
Drenching rain has amplified the misery for tens of thousands of Monrovians packed into the diplomatic quarter to escape the fighting, where many had no shelter or huddled under scraps of plastic sheeting.
On Monday, angry Liberians piled up the bodies of victims of the latest bombardment outside the American embassy in protest at apparent US reluctance to deploy peacekeepers.
Mortar bombs had fallen on the diplomatic quarter as people were out seeking water and supplies, and at least 60 were thought to have been killed inside an hour.
"If they do not value our lives and come and help us, then they should just leave," said one Liberian.
The US, which has historical ties to Liberia, is however preparing to move a naval force to the region for possible deployment - but has not specified how it would help.
Some 250,000 people are living rough in appalling conditions in the capital and doctors are struggling to treat an ever-growing number of casualties.
A UN official warned that civilians now had nowhere to run to escape the fighting.
"There is no shelter, no food, no water," Muktar Farah of the UN Office for the Coordination of Humanitarian Affairs told Reuters news agency. "If fighting continues... this will be a humanitarian catastrophe."
The pumping station that supplies water to Monrovia was hit over the weekend and aid agencies say that, unless the pumps can be repaired, cholera is likely to spread.
Diesel fuel and rice are also in short supply, with the port now in rebel hands and the airport closed.
Despite the killing in Monrovia, a regional peacekeeping force still appears some time away from intervening in the crisis.
The chiefs of staff from 10 of the Ecowas countries have been meeting over the past two days to discuss details of an initial force of up 1,500 personnel, expanding to 3,000 - the majority from Nigeria and the rest from Ghana and Mali.
Foreign ministers are due to meet on Wednesday in Senegal to decide whether to send in the force, but in Nigeria, President Obasanjo has said no troops will be deployed until a ceasefire is in place.
He insists the safety of Nigeria's soldiers is a primary concern.
Hopes of a resolution appear hampered by the conditions each party is attaching to their involvement:
The Lurd (Liberians United for Reconciliation and Democracy) rebels say their latest offensive against the capital is in response to violations of a 17 June ceasefire by President Taylor's troops last week
The US - which many Liberians wish to see leading a peacekeeping force - has accused the rebels of violating the ceasefire themselves; it has urged Mr Taylor to leave office, and is keen only to intervene once a West African force is in place
Mr Taylor has accepted an offer of political asylum from Nigeria but says he will not leave until international peacekeepers arrive; he has also vowed to fight the rebels to the "last man"
Nigerian President Olusegun Obasanjo, whose country's troops will be a key component of any West African force, has said that Ecowas peacekeepers can only be deployed in the event of a ceasefire.
The US has announced it is moving about 4,500 marines and sailors to the Mediterranean for a possible role in Liberia.
However, President George W Bush appeared to suggest their role would be to help deploy an African force rather than to serve as actual peacekeepers.