Rebel troops have renewed their assault on the Liberian capital, Monrovia, with heavy fighting around two key bridges.
Monrovia's main football stadium has become a refugee camp
The BBC's Jonathan Paye-Layleh in Monrovia says this is the closest the rebels have been to the city centre.
Further south, the second city of Buchanan is reported to have fallen to another rebel group, according to an aid worker there.
In recent weeks, thousands of Liberians have fled there to escape the fighting in Monrovia.
Meanwhile, a source at a meeting of West African military chiefs in Ghana said no date had yet been set to deploy peacekeepers.
The Nigerian general who would lead any West African peacekeeping force says it is "unlikely" any troops will be deployed this week.
Water and food are running short for residents of the capital, whose numbers have been swelled by up to 250,000 refugees.
Hundreds have been killed and thousands injured in the latest nine-day assault on Monrovia.
On Sunday, loyalist fighters managed to retain control of the Gabriel Tucker and Old Bridges, which lead to central Monrovia.
Our correspondent says that the shelling, which has caused heavy civilian casualties in recent days, subsided on Monday as the two sides exchanged small arms fire.
"We managed to hold them off at the bridge and push them back," army chief of staff General Benjamin Yeaten told Reuters.
The Movement for Democracy in Liberia (Model) group has been fighting government troops around Buchanan for several days.
General Yeaten confirmed that rebel fighters had entered the port town of Buchanan.
But speaking at 1700 GMT, Merlin aid worker Edward Kwame, told the BBC's Focus on Africa from the outskirts of the city that it appeared the town had fallen to the rebels after a stand-off.
The main Lurd rebel group is also being reported as saying they have taken control of the town of Gbarnga, to the east of the capital.
Officials from the regional body Ecowas are meeting in Ghana to discuss sending a force of some 1,300 Nigerian troops to Liberia.
Ecowas officials had said the force could be deployed this week but Nigerian Brigadier General Festus Okwonkwo, who would lead the force, cast doubt on this.
When asked when the force would go in, he said:
"No day, no date, don't know."
"We're still mobilising logistics, the logistics are not yet ready. As soon as they are ready and we are asked to go in, we will go in."
West Africans want the peacekeepers to be led by United States troops and three US warships are heading for the Liberian coast.
But President George W Bush says the troops will not land until a ceasefire is in place.
The rebels have rejected a US plea to both sides to respect a ceasefire and for the rebels to withdraw to the River Po, 12 km from central Monrovia.
They want Mr Taylor to step down. He has agreed to go - but only when peacekeepers arrive.
Reuters news agency reports that people were collecting rain-water to drink during Monday's heavy downpours.
"We are dying of hunger and sicknesses."
Magnus Wolf-Murray of the medical aid agency Merlin says water is in desperately short supply.
"Around central Monrovia there are 100,000 people who are relying on just a few wells," he said.
Deadly bombardments have struck residential areas, schools and churches crowded with refugees.
Each side has blamed the other for bombarding civilian areas.