"Congolese officials should fulfill their obligations... towards the victims of such atrocious acts and their families to whom justice must be rendered,? the head of the UN mission in the country, MONUSCO, said in a statement.
Its joint investigation with the UN human rights agency recorded 135 cases of sexual violence committed by the regular army in and around the city of Minova in November 2012, MONUSCO chief Martin Kobler noted.
According to Human Rights Watch, soldiers went on a 10-day raping and looting rampage in the area while they were fleeing an offensive by rebels of the March 23 Movement (M23) on the main city of Goma, further north.
"Almost a year after these incidents, none of the presumed perpetrators of these human rights violations has been brought to justice... in spite of the Congolese authorities? commitment to prosecute the perpetrators," the MONUSCO statement said.
The DR Congo government signed an accord with the United Nations in April to step up the fight against sexual abuse by armed groups and soldiers, which remains rampant mainly in the volatile east of the country.
The feeble DR Congo army has been much criticised for its brutality against civilians and corruption. UN officials said it "melted away" during the M23 advance on Goma, which the rebels took over on November 20 and held for nearly two weeks.
MONUSCO also recalled in the statement that the investigation identified 59 cases of sexual violence committed by M23 fighters in the Goma area during the same period.
The DR Congo army is heavily reliant on UN equipment and military support in its efforts to control the armed groups that hold sway in the resource-rich region