One of the rebel leaders fighting in Congo says his troops have killed 80 government soldiers in the north of the country.

The leader of the Congolese Liberation Movement (MLC), Jean-Pierre Bemba, said the soldiers were killed as they neared the rebel town of Libanda by canoe, along the Congo river.

"During the night they [government soldiers] tried to approach the town but we made an ambush and killed 80 men, hitting and destroying two canoes," he told Reuters news agency by phone from northern Congo.

There has been no independent account of the ambush.

The leader of the Ugandan-backed rebel group said government troops had attacked three towns in the past few days - Libanda, Nkonya and Dongo - but had been repulsed by rebels.

He said rebels had retaken Nkonya three days ago, after government troops briefly captured it earlier this month.

Congolese President Laurent Kabila, who is supported by troops from Zimbabwe, Angola and Namibia, has been unable to put down rebel groups backed by Uganda and Rwanda that control the north and east of the country in fighting over the past 16 months.

A peace deal signed in the Zambian capital, Lusaka, in July has done little to stop fighting on the north-west front.