A Congolese rape victim (left) and a child are pictured at the Heal Africa clinic in Goma. File photo: AFP

Kinshasa - Democratic Republic of Congo troops went on a rape rampage, attacking at least 135 women and girls as they retreated from a rebel advance in 2012, according to a UN report released on Wednesday.

Soldiers raped women at gunpoint, killed a boy who tried to save his goat and beat men who tried to defend their wives and homes, according to the latest harrowing episode from more than two decades of conflict in eastern DR Congo.

UN human rights investigators said the army and M23 rebels, who routed government forces as they took the major eastern city of Goma in November, could face international crimes against humanity charges.

Congo authorities should promptly bring to trial rebel and army commanders “regardless of their rank”, said the investigators. They also called on “neighbouring states” to hand over M23 leaders implicated in the atrocities.

M23 fighters carried out a rape and killing spree in Goma as they took over on November 20 with UN peacekeepers powerless to stop them alone.

Thousands of DR Congo army troops retreated to Minova in South Kivu province where they went on their own rampage in the town and eight surrounding villages.

According to a toll given by the UN investigators, 17 people, including two boys, were killed in the weeklong offensive to take Goma.

During their 10-day occupation of Goma and the nearby town of Sake, “at least 11 civilians were arbitrarily executed” and there were 58 rapes by M23 fighters.

M23 took over a Goma military camp where at least 49 women - mainly the wives of soldiers who had fled - were raped or sexually assaulted, said the report.

The militia also forcibly recruited child soldiers and slave labour.

But the UN investigators said they were “particularly concerned about the gross human rights violations perpetrated by the Congolese army” around Minova.

At least 102 women and 33 girls were victims of rape or other acts of sexual violence by government troops, said the report, based on more than 350 interviews with witnesses and victims.

The attacks were “perpetrated in a systematic manner and with extreme violence,” said the investigators.

Two people were “arbitrarily executed” while other civilians were forced to carry the pickings from the “widespread looting of villages” by the army, known as the FARDC.

Troops entered homes and “looted whatever they could find,” said the report.

“One or two of the soldiers would leave with the looted goods and at least one would stand guard as the remaining FARDC soldiers raped women and girls in the house.”

Soldiers beat two men who tried to prevent the rape of their wives, said the report, and a man died after being hit with a rifle butt and punched as he tried to resist the looting.

One 14-year-old boy was killed as he tried to stop two soldiers stealing his goat. “As he tried to resist and flee, one of the soldiers shot him.”

The offenses could “constitute war crimes and crimes against humanity” under the statute that set up the International Criminal Court, said the report.

M23 founder Bosco Ntaganda surrendered to the court last month after fleeing to the US embassy in Rwanda, which has been accused of backing the rebel group.

Eleven DR Congo soldiers were arrested in December: two for murder but “only” two for the rapes, the report said. The Congo government has since suspended 12 senior officers in charge of the units implicated in the rapes.

Action was only taken after the UN threatened to end cooperation with the army's 391st and 41st battalions which had been in Minova.

The report said the government had to make sure there were prompt trials of M23 and army soldiers guilty of violations “including those bearing command responsibility, regardless of their rank.”

The report said the international community was responsible for “verifying conformity with human rights standards” in DR Congo.

Without naming any country it said “neighbouring states” - a veiled reference to Rwanda - should help DR Congo detain and try M23 leaders.

Rwanda has denied a report by UN experts who said M23 had been given military help by the country. - AFP