Thousands of Monrovia residents on Thursday fled as fighting became fiercer near the capital center, according to reports from Monrovia.
The fighting between rebels of Liberians United for Reconciliation and Democracy (LURD) and government troops loyal to President Charles Taylor occurred at three key bridges, Stockton Creek Bridge linking the rebel-held port with the airport, and Johnson and Old Bridges leading to the city center.
"We're defending our positions on the bridges," Liberia's Defense Minister Daniel Chea was quoted as saying.
"There's a very thin line between our forces and theirs," he added.
On Wednesday evening, LURD rebels fought their way forward some800 meters into the line controlled by the government troops after crossing Stockton Creek Bridge.
But the government troops drove them back later and the rebels had no way to go but withdrew by crossing the bridge back, said a government military source.
The fighting erupted last Friday reportedly killed up to 700 civilians and displaced some 200,000 people.
As the bloody fighting entered its seventh day, residents in the capital city now faced severe shortage of food and water.
"Stocks of food and water are running low, malnutrition is widespread and tens of thousands of people do not have access to drinkable water," said Marc Destanne de Bernis, the UN humanitarian coordinator for Liberia.
According to him, there will be "one of the worst humanitarian tragedies in the region," if the fighting does not stop immediately.
Although Nigeria had promised to send two battalions of 1,500 troops to Liberia as vanguard peacekeepers, Economic Community of West African States Executive Secretary Mohamed Ibn Chambas said Tuesday that at least 5,000 would be required.
The Liberian civil war, which lasted about 15 years and claimed at least 200,000 lives, flared up again in 1998 following attacks launched by the LURD rebels in northern Liberia.
Civil war over the past decade has made Liberia among the most miserable places in the world and the latest unrest since 1998 has forced some 300,000 Liberians to flee to neighboring countries and claimed thousands more lives.