The release of the report appears to have been delayed in part over fears of the reaction of the Rwandan government, which has long enjoyed strong diplomatic support from the United States and Britain. There is concern in the United Nations that Rwanda might end its participation in peacekeeping operations in retaliation for the report.

“No one was naïve enough to think that inspecting mass graves in which Rwandan troops were involved would make Kigali happy, but we have shared the draft with them,” said a senior official at the United Nations High Commission for Human Rights in Geneva, which oversaw the investigation. The official spoke on the condition of anonymity because the findings had not been officially released.

He said: “Voices have said, ‘Can’t we just delete the genocide references? Isn’t this going to cause a lot more difficulties in the region?’ But these voices have not carried the day.”

The United Nations document breaks the history of 10 years of violence in Congo into several periods. It begins with the final years of the three-decade rule of President Mobutu Sese Seko, marked by attacks on a Tutsi minority in the country’s far east, and violent raids on Rwandan territory from United Nations-administered refugee camps that housed roughly a million Hutu who had fled Rwanda after the genocide. These raids were conducted by elements of the defeated Hutu national army, and the Hutu Interahamwe militia, both principally involved in the genocide in Rwanda.

The report also covers two other time periods: the Second Congolese War, from 1998 to 2001, when the armies of eight African states vied for control of the country, and 2001 to 2003, when foreign armies partially withdrew, leaving a tentative peace. Congo continues to suffer major atrocities, including the rape of thousands of women by armed groups.

The report contains a chilling, detailed accounting of the breakup of Hutu refugee camps in eastern Zaire at the start of the war in October 1996, followed by the pursuit of hundreds of thousands of Hutu refugees across the country’s vast hinterland by teams of Rwandan soldiers and their Zairean rebel surrogates, the Alliance des Forces Démocratiques pour la Libération du Congo. Those forces were led by Laurent Kabila, who took over as president the next year, and who was the father of Congo’s current president, Joseph Kabila.