By Greg Barrow BBC United Nations correspondent in New York

One of the main rebel groups in the Democratic Republic of Congo was responsible for a massacre in the eastern town of Kisangani earlier this year, a report by the United Nations Human Rights Commission says.

The report, presented to the UN Security Council in New York by UN Human Rights Commissioner Mary Robinson, says up to 180 people - the majority of them civilians - were killed in reprisal attacks by gunmen from the RCD Goma rebel faction after a mutiny.

Civil war has ravaged Kisangani

Shortly after the killings, the rebels called for the removal of the UN special envoy in Congo, after the UN accused them of grave human rights violations.

The report describes in detail what may turn out to be one of the worst massacres by rebel groups in DR Congo.

It says more than 100 civilians and up to 80 police officers and soldiers were killed during massacres that followed the mutiny.

The report suggests that the excessive violence used by the rebel troops was prompted partly by a radio broadcast by the mutineers urging local people to kill any Rwandans in Kisangani. The RCD Goma rebel faction is supported by the Rwandan Government and has become increasingly unpopular among local Congolese.

Nevertheless, the violence unleashed on local people appears to have been excessive. Some were killed during indiscriminate shooting; others were executed, hacked to death with machetes or had their throats slit.

The report gives one particularly grisly account by witnesses of soldiers being executed on a bridge outside Kisangani; their bodies were then thrown into the river.

'Feeble cover-up'

RCD Goma carried out its own investigations into the massacres and concluded that only 41 people were killed. But the UN Human Rights Commission describes the RCD Goma investigation as a feeble attempt to cover up the massacres and protect the perpetrators.

The report notes that the local population in Kisangani appears deeply opposed to the presence of the RCD Goma group's Rwandan allies.

It says the situation in the town remains fragile and that further bloodshed should not be ruled out.