One woman was killed and nine locals were abducted in the Feb. 1 attack on the village of Kakenge in south Kivu province, which follows allegations last year that government forces killed, raped, and mutilated hundreds of civilians.
It comes as the U.N. force MONUC appraises its support for an imminent Congolese assault on the rebels as part of Congolese operations seen as vital to wider peace in central Africa.
MONUC spokesman Lt Col Jean-Paul Dietrich said FARDC Congolese army troops initially prevented a U.N. patrol from entering the village to probe the incident.
“Investigations conducted afterwards indicated the probable implication of FARDC in the incident,” he told a news conference.
“It is disturbing, if we are to work jointly with FARDC, that we are not allowed access or given information.”
According to a local leader quoted by U.N.-backed Radio Okapi, the violence lasted three hours and took place within 100 metres (yards) of FARDC positions.
“Some behaviour by our commanding officers seems to justify the suspicion,” said Capt Olivier Hamuli, an FARDC spokesman in South Kivu who was part of a joint MONUC-FARDC investigation team visited Kakenge on Tuesday.
“All those who may be implicated will be held accountable before military courts,” Hamuli said.
The government of Congo has been struggling to reestablish control over the east since a 1998-2003 war and accompanying humanitarian disaster that have killed 5.4 million people.
It launched operations against FDLR Rwandan rebels, some of whose members participated in Rwanda’s 1994 genocide, in March 2009 with the logistical support of the United Nations.
Humanitarian agencies criticised the offensive, during which more than 7,000 women and girls have been raped and more than 900,000 people forced to flee their homes.
According to the U.N., some 2,300 FDLR fighters have been sent back to Rwanda as a result of that operation and a previous offensive conducted by Congo and Rwanda in early 2009. It is unclear how many were killed or recruited in the same period.
The United Nations is discussing a new mandate for the Congolese force, which at more than 20,000 is the biggest U.N. operation in the world.
President Joseph Kabila, whose country is celebrating the 50th year of its independence from Belgium on June 30, is believed to want a reduced presence. But U.N. sources say any withdrawal would be gradual and dependent on security.
(Reporting by Thomas Hubert; editing by Mark John and Michael Roddy)