The refugees are fleeing fighting in the province of South Kivu between rebels and pro-government militias known as the Mai Mai.

Civilians are also being trapped by clashes between different factions of the Mai Mai themselves.

The UNHCR says the past few days have seen a dramatic increase in the number of people trying to flee.

'Catastrophic situation'

Since the conflict began last August, tens of thousands of civilians have crammed onto boats - to be ferried to safety across Lake Tanganyika.

Among the recent arrivals were two Italian priests who described the humanitarian situation in the province of South Kivu as catastrophic.

Women refugees have told of being forced to provide domestic and sexual services for Mai Mai fighters.

And civilian men wearing traditional skin markings have been captured by rebels who accuse them of being Mai Mai sympathisers.

Slow progress in talks

Talks in Lusaka aimed at ending the Congo conflict have made slow progress so far this week, and on Wednesday evening there were fears that negotiations would break down completely.

The government of President Laurent Kabila is facing a rebellion by various groups based in the east of the country, who have succeeded in seizing about a third of DR Congo territory.

The rebels enjoy the support of Rwanda and Uganda, while the Congolese government has received the backing of Zimbabwe, Angola and Namibia.