More than 1,000 Nigerian peace-keepers will be sent to Liberia within a week, West African leaders have said.
People are queuing for food... aid agencies warn of disaster
Speaking in Senegal, the head of the West African regional grouping Ecowas, Mohammad ibn Chambas, told the BBC he hoped all Liberians would respect a ceasefire.
He said the United States - which is under increasing pressure to send troops to the county - would help pay for the deployment.
The BBC's Paul Welsh in Monrovia says news that regional peacekeepers have been promised is being greeted with scepticism, as troops were first pledged more than a month ago.
A top aide to President Charles Taylor in Ghana, Lewis Brown, said the embattled Liberian leader would leave the day the Nigerian troops arrive, reported Associated Press news agency.
Fighting has continued for a fifth consecutive day in the capital.
Government forces have reportedly driven rebels from the key Stockton Bridge which offers a route to the airport and the centre of the city.
Civilians are fleeing the capital where several hundred people are believed to have been killed in the past few days.
Reports say American military helicopters have flown into Monrovia, bringing reinforcements to protect the US embassy compound and to ferry out 17 aid workers and foreign journalists.
Corpses have been piled outside the US embassy in protest at the lack of
British aid agencies have joined the appeal for Europe and the US to send peacekeepers to the war-torn country.
Signed by a several organisations, including Save the Children and Christian Aid, a statement accused President George W Bush of "prevaricating".
"The rest of the world has stood by as Liberia has disintegrated
once more into chaos," they said.
Former US envoy to Africa Jesse Jackson has also criticised President Bush for not sending troops to Liberia.
"Liberia's been a long time ally, and we are on the verge of betraying Liberia for a second time. The silence of Secretary [of State Colin] Powell, security chief [Condoleezza] Rice and Mr Bush is deafening," he told the BBC's World Today programme.
Aid agencies have warned of a humanitarian disaster in Monrovia as they try to help some 250,000 people who have nowhere to live after fleeing to the capital.
Water, diesel fuel and rice are in short supply, with the port now in rebel hands.