After several hours of fighting the rebels dissolved into the jungle, but on Thursday morning they returned to engage government troops again, according to military sources.

The BBC's Jonathan Paye-Layleh in Monrovia says dozens of civilians have died in the fighting, and many more were abducted by rebels when they retreated overnight.

Humanitarian crisis

In recent weeks Lurd rebels have used the town of Bopolu, 100km north of Monrovia, as a base for attacks on towns in the surrounding Bomi county.

Ten of thousands of people have fled their homes in north-west Liberia.

Most of them are living in camps in the Monrovia area.

Last November aid agencies withdrew from Bopolu because of the fighting.