Liberian troops are battling a fresh rebel attack in the centre of the capital Monrovia after President Charles Taylor vowed his forces would fight to the last man.
At least five people were killed when a mortar bomb landed among residents a few hundred metres from the US embassy, witnesses said.
Tens of thousands of people have flocked to the heart of the city in search of sanctuary, distraught that promised regional peacekeepers have failed to show up in time to prevent a third rebel assault on Monrovia in little more than a month.
Mr Taylor accused the United States on Saturday of having "blood on its hands" for urging him to step down while he was trying to beat back the rebels. Washington says a small US peacekeeping force may be deployed once Mr Taylor leaves.
Government troops said they had fended off advancing rebels from the key Gabriel Tucker bridge, the gateway to central Monrovia. Witnesses said there was heavy fighting around the bridge and another crossing point into the core of the city.
Defence Minister Daniel Chea said loyalist forces were also battling rebels who had tried to capture a road that cuts around the back of the swampy city to the area where Mr Taylor has his residence and towards the road leading to the main airport.
On Saturday, rebels of Liberians United for Reconciliation and Democracy (LURD) broke through Monrovia's northern district firing a barrage of mortar bombs. More mortar rounds rained into the city centre on Sunday, some hitting the diplomatic quarter.
LURD accused Mr Taylor in a statement on Sunday of attacking its positions in violation of a June 17th ceasefire signed in Ghana.<