The Revolutionary United Front (RUF) rebels forced a West African peace- keeping force to retreat from Makeni, triggering the flight of the town's entire population of several thousand.
The RUF has launched a series of offensives in recent weeks to recapture ground lost to the Nigerian-led peace-keepers earlier in the year.
Diplomats from West Africa, the United States and Britain, meeting on Monday in the Ivory Coast capital of Abidjan, called for more aid to help defend Sierra Leone's embattled government.
Nigeria has assumed themajority of responsibilities for the peace-keeping force, known as Ecomog. The US and Britain have provided logistical support for the regional task force.
Rebel units claim to have come within 12 miles of the capital and have threatened to start shelling the city. Sierra Leone claims that mercenaries from Liberia, Burkina Faso and Ukraine are fighting alongside the rebels, though that has not been independently confirmed.
Nigeria flew two more battalions to bolster its forces in Freetown on Sunday night. The peace- keepers are also expecting reinforcements from Gambia.
President Kabbah has offered to negotiate with the rebels but they have declined, claiming they will storm the capital unless he resigns. The fighting has forced most foreign nationals to leave the country.