Beni: One person was killed and at least seven seriously wounded on Saturday as police opened fire on a crowd protesting against militant attacks in northeastern DR Congo.

Protesters have staged several rallies against local forces and UN peacekeepers for failing to stop militant attacks in the city of Beni since Wednesday, when seven civilians were killed in the latest assault.

Military officials said they had detained two police officers after Saturday's incident and launched an inquiry into the circumstances of the protester's death.

The Allied Democratic Forces (ADF) - a militia that originated in Uganda in the 1990s - have killed more than 60 civilians in the Beni region since the military announced a new effort to defeat them at the start of November.

"The doctor just told us that Obadi (a demonstrator) is dead. We just took his body to the morgue," Ghislain Muhiwa Kasereka, a spokesman for the pro-democracy Lucha movement told AFP in Beni's main hospital.

Military prosecutors also confirmed the death, adding that six or seven demonstrators and one policeman were in a critical state in hospital.

An AFP journalist said police opened fire in the heart of the city, near the hospital and the town hall.

The ADF began as an Islamist rebellion hostile to Ugandan President Yoweri Museveni. They later moved into eastern DR Congo in 1995 and have recruited people of different nationalities, but appear to have halted raids inside Uganda.

The UN peacekeeping mission in DR Congo, known by its French initials MONUSCO, stressed on Saturday that the Congolese army had launched its anti-ADF offensive unilaterally.

"MONUSCO cannot engage in operations in a war zone without being asked and without strict coordination with the national army," it said on Twitter, adding that uncoordinated action could lead to friendly fire.