A Congolese soldier was also killed and a civilian injured in separate clashes with Uganda's Allied Democratic Forces (ADF) rebel group in the eastern region of Beni, army spokesman Captain Mak Hazukay said.
The latest violence in the restive provinces of North and South Kivu underscores the fragility of a region which has been wracked by ethnic and rebel violence since the mid-1990s.
The ten charred bodies were found today in South Kivu after clashes involving three ethnic groups, the Banyamulenge, Bafuliro and Banyindu, the official in charge of the Tanganyika sector John Mwimiwa said.
The Banyamulenge, or Congolese Tutsis, are regarded as foreigners by the other two ethnic groups and often clash with them. Each has their own militia.
"Several villages were attacked yesterday by the Ngumino militia and the Forebu (Popular Forces of Burundi) rebel group active in the Uvira and Fizi districts," Mwimiwa said.
"We deplore the deaths of 10 persons in fires. All those killed were displaced people and were burnt in their huts." The UN's Office for the Coordination of Humanitarian Affairs (OCHA) said 76,000 people had been displaced in the region this year due to violence between the three groups.
Claude Misare, the head of a local NGO, said the dead included four children and two women.
The villages are located about 200 kilometres west of Uvra, the second largest town in South Kivu province.
"We were eight in all on four dugout canoes when the Ugandan patrol boats approached us on the night of Friday to Saturday," said Sikuli Mukosa, a 40-year-old fisherman.
"They asked us for our identity papers and then fired at our boats. I played dead. My seven comrades died," Mukosa told AFP.
"Since Thursday, the Ugandans have deployed greater forces than mine on the lake," he said.
The Congolese navy is tasked with preventing militia fighters and local rebels and others from neighbouring countries from operating in the area.
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