The disarmament programme appears to have been a success

Officials say that more than 70,000 fighters have laid down their weapons, nearly double initial estimates. At least 15% were child soldiers.

Most observers say the programme has been fairly successful despite a bad start on Friday, when around seven people died in a riot.

The uncertain situation has also forced the UN to postpone repatriation of refugees from neighbouring Guinea.

A spokeswoman said the refugee agency had hoped to get the repatriation process under way on Saturday, but it had a policy of not returning people to unsafe environments.

She said the repatriation exercise would be started as soon as it became safe to do so.

'Hooligans'

On Saturday Liberia's interim leader Gyude Bryant prolonged a curfew imposed after the riots for another night.

The violence is a reminder of how volatile Liberia remains

It is not clear what sparked the violence, which began on Thursday evening in the commercial suburb of Paynesville and spread across the capital to other districts including the port area.

Several churches and a mosque were burned down.

Mr Bryant said hooligans were to blame, but there are reports that former fighters were involved.

The BBC's David Chazan says many are angry at a lack of work and training, but the UN is trying to help solve the problem by putting thousands of child fighters into school.

But the violence was a reminder of how volatile Liberia remains, our correspondent says, and raises questions about the thoroughness of disarmament in a country still awash with guns.

The unrest was one of the most serious outbreaks of violence in Liberia since former President Charles Taylor went into exile in August last year as part of a peace deal to end 14 years of civil war.

Mr Bryant heads a transitional power-sharing government set up to organise elections.