Ten civilians and a Ugandan militant died when Congolese troops clashed with rebels in the flashpoint town of Beni in Democratic Republic of Congo's troubled east, an army spokesman said Wednesday.
The incident took place on Tuesday evening when rebels attacked military positions around Beni in North Kivu, Captain Mak Hazukay told AFP.
"We listed 10 dead civilians so far," he said.
A rebel from Uganda's Allied Democratic Forces (ADF) militia was also killed, he said, adding that fighting was ongoing.
Michel Kakule, the lead physician at Beni hospital, told AFP some of the victims "had gunshot wounds while others had been attacked with machetes."
The violence sparked an angry backlash among locals "who blocked off several main roads in the town in protest over the murder of 10 civilians," said Gilbert Kambale, who works for a civil society organisation.
Since January, Congolese troops have been engaged in a major military operation against the ADF but it has not managed to stop the bloodshed in and around Beni.
The ADF "is now conducting an asymmetrical war -- when we attack them in one area, they get around it by attacking elsewhere," said Hazukay.
The ADF is one of a number of armed groups that hold territory in the eastern DR Congo and are battling for control of the region's rich mineral resources.
The militia group, which was created by Muslim radicals to oppose the rule of Ugandan President Yoweri Museveni, has been present in the North Kivu area since 1995 where it stands accused of killing several hundred civilians in the past three-and-a-half years.
It has also been accused of killing 15 UN peacekeepers from Tanzania in a deadly attack in the Beni area in December.
DR Congo's restive east has been wracked by violence for the past 20 years.
On Tuesday, the UN Security Council renewed the mandate of its huge MONUSCO peacekeeping mission in the country for another year, tasking it with helping prepare for December elections aimed at ending the rule of President Joseph Kabila.
With more than 16,000 troops on the ground, it is the UN's biggest peacekeeping mission and has been present in the country since 1999.
But the DRC's ambassador to the UN, Ignace Gata Mavita, said the mission's focus should be fighting rebel groups rather than supporting elections.
Its role should be "to combat armed groups to protect civilians and restore peace and security in the east of our country," he said
The ambassador also renewed calls for MONUSCO's exit from the DRC. The origins of the UN peacekeeping mission go back nearly 20 years