Congo's main rebel army said it had recaptured the eastern lake port of Uvira today after heavy overnight fighting in which scores of civilians and soldiers were killed.
"We attacked just after midnight and three hours later we were in control of the town," Mr Jean-Pierre Lola Kisanga, spokesman for the Rwandan-backed Rally for Congolese Democracy (RCD), told reporters by phone from Goma.
"About a 100 people were killed, some of them civilians," he added.
The town at the northern end of Lake Tanganyika was captured by tribal militias earlier this week. The RCD said the militias were acting under direct orders from President Joseph Kabila, a charge the Kinshasa government has strongly denied.
Kisanga said government soldiers were among 51 prisoners taken by the RCD.
"They had government uniforms and identity cards," Mr Kisanga said, adding that the RCD had suffered an unknown number of casualties.
Recent fighting in eastern Democratic Republic of Congo has set back advances in a peace process that saw the retreat of most foreign armies from Africa's third largest country.
International pressure recently improved relations between the main belligerents, but local violence has flared in the wake of retreating national armies.
The war in former Zaire started in 1998 when Rwanda and Uganda backed separate rebel armies trying to topple Kinshasa's government, which has been propped up by Zimbabwe, Angola and Namibia.
More than two million people have died, most from starvation and hunger.