Congolese rebels fought government forces in eastern Congo Thursday on the eve of a regional summit on the crisis and despite a recent cease-fire, U.N. officials said.
Madnoje Mounoubai, a spokesman for the U.N. mission in the Democratic Republic of Congo, said Laurent Nkunda's rebels had battled government forces in Nyzanale on Thursday, reported CNN.
Nkunda, who declared the cease-fire, told The Associated Press television his forces were attacked outside Mweso, not far from Nyzanale.
"We were attacked three times," he said.
"Cease-fire is not saying that when you are attacked you cannot react. They have the right to defend, and the good defense is offense."
It was not clear who controlled Nyzanale afterward.
The clashes marked the third straight day of fighting, despite a unilateral cease-fire that Nkunda declared on October 29.
Media reports and an official with the U.N. military said Thursday's fighting had forced thousands of people from their homes.
A summit in Nairobi, Kenya, will be held Friday on the crisis. U.N. Secretary-General Ban Ki-moon and Congo President Joseph Kabila, Rwandan President Paul Kagame, and Tanzanian President Jakaya Kikwete -- the African Union chairman -- are expected to attend, the United Nations said.
The United Nations released a statement Thursday saying the secretary-general "is deeply concerned about the ongoing violence in the eastern Democratic Republic of the Congo."
The secretary-general "calls for an immediate cessation of hostilities and the withdrawal of forces to positions held prior to the resumption of fighting on 28 August," the statement said, referring to when the latest wave of fighting broke out.
Ban "urges the armed groups involved in the ongoing fighting to support the current efforts to find a political solution to the crisis in the eastern DRC and to avoid activities that result in the further displacement and suffering of the civilian population."
On Wednesday, Nkunda's forces -- the National Congress for the Defense of the People -- fought Mai Mai forces, or pro-government local militias, in Kiwanja, also in eastern Congo, said Kevin Kennedy, a spokesman for the U.N. mission.
"We encourage all the groups to restore the cease-fire," he said.
Nkunda said his forces had not broken the cease-fire.
"We declared for a cease-fire, it was a unilateral cease-fire. And we ask the government to stop the attacks, even their allies," he told CNN Thursday.
"So they attacked us," he said.
"What we are asking for is only a cease-fire, then we go for peace talks and we ask the government to accept us through talks and to have a neutral mediator. That's what we are asking. It's not so many things."
The rebel leader said the Mai Mai had been dressed in civilian clothing during Wednesday's fighting, and he vehemently denied allegations that his forces had killed civilians.
"It's not true," Nkunda said. "These Mai Mai, these militia were in civil dress. ... We asked the civilian population to get behind the front lines. So, the population were behind the front line," he said.
"We cannot kill a civil population," he said.
On Tuesday, the rebels battled Mai Mai fighters near Rutshuru, near Kiwanja.
Medecins Sans Frontieres (Doctors Without Borders) said surgical teams had treated 50 people from Wednesday and Thursday's fighting.
"Thousands of people who have fled the fighting in Kiwanja have sought shelter on the road between the two towns, in churches, and even inside Rutshuru hospital," MSF said. It did not say if the people treated were civilians.
Anne Taylor, the head of the MSF mission in Goma, issued a statement saying, "MSF provides health care to all patients without discrimination."
Around 250,000 people were displaced as a result of fighting in recent months, the United Nations estimates.
Tensions in the Congo have festered since its civil wars in the mid-to-late 1990s and since the 1994 Rwandan genocide.
Nkunda, a Tutsi, has repeatedly blamed the Congolese government for failing to protect the Tutsi tribe from Rwandan Hutu militia in Congo. Critics have alleged Nkunda to be a puppet of Rwanda.
The ongoing conflict and humanitarian crisis kills 45,000 people in Congo every month, according to a January 2008 report from the International Rescue Committee.
Hutu rebels have been active in the jungles of eastern Congo since Rwanda's 1994 genocide, according to the United Nations. During the 100 days of that genocide the Hutu majority killed 800,000 Tutsis and moderate Hutus, the United Nations estimates.