|Kagame and Ban Ki Moon in Madrid|
The 60-page document, co-authored by four former senior officials turned opponents in exile, paints a damning picture of the state of political and individual freedoms in the small genocide-scarred central Africa nation.
"A minority government as repressive and unaccountable as Rwanda?s current regime cannot remain in office forever," said the report.
"The people of Rwanda, together with rest of the international community, have a moral duty to work to end this repressive system of government. Rwanda is literally again on the brink of an abyss," it said.
Kagame was sworn in for a second -- and what should be a final -- term in office Monday at a ceremony attended by 40,000 supporters and regional heads of state, a month after sweeping to re-election with 93 percent of the vote.
Rights groups have consistently decried the lack of freedom in Rwanda and slammed what they described as a climate of fear during an electoral campaign marred by arrests and killings.
The report, authored notably by two prominent security officials who claim to have been the target of government persecution and currently reside in South Africa, called for an inclusive dialogue on the future of the country.
"Implementation of the outcome of dialogue could be entrusted to a coalition government that includes the opposition that is currently excluded from political participation," the document said in its conclusion.
Among the authors are General Faustin Kayumba Nyamwasa, who survived a June assassination attempt in South Africa, and Patrick Karegeya, a former intelligence chief who fled Rwanda in 2007.
The other two are Theogene Rudasingwa, a former Kagame chief of staff and ambassador to the United States, and Gerald Gahima, former prosecutor general and vice president of the supreme court.
Kagame, who has ruled Rwanda since his rebel group ended the 1994 genocide against his Tutsi minority, is facing a growing challenge from former comrades-in-arms who are now accusing him of dictatorial tendencies.