Fearing reprisal, thousands of Congolese Tutsis have fled across the nearby border into Tutsi-run Rwanda.
The enemy - the Rwandan Patriotic Front or RPF - had been formed among Tutsi exiles in Uganda.
The rebels' protestations that they are Congolese and their leader is not a Tutsi, will not be believed.
But many Burundians, including those among the Tutsi minority, are waiting see how the FDD will govern in practice.
Likewise, Congolese Tutsi businessmen serve as a Rwandan vanguard, opening up eastern Congolese land for cattle grazing and mining.
ECONOMIST: The latest rebellion in eastern Congo does no one any good
Bizima Karaha, Mr Kabila's former foreign minister and the most articulate of the civilian rebel leaders, is a Tutsi.
It is urgently seeking a formula that would be reasonably democratic and, at the same time, protect the Tutsi minority.
Mr Buyoya argues that he is the only man who can pull this off, as the Tutsi generals trust him.
Though Tutsis account for only a small proportion of Rwanda's population, the most powerful people in the government are all Tutsi.
In 1990, Kagame was attending a training course at Fort Leavenworth in the U.S. state of Kansas when Tutsi rebels invaded Rwanda.
CNN: From child refugee to Rwanda's reconciliation president
The two Hutu rebel groups, who remain outside the peace process, have been fighting against the minority Tutsi dominated army since 1993.
The victims were mostly from the Tutsi ethnic minority, who were targeted by Hutus over a rivalry that dates to colonial days.
Ethnic friction arose when colonial Belgium built an alliance with Tutsi leaders, a ruling class that was overthrown by Hutus in 1959.
FORBES: In Global Arms Trade U.S. Taxpayers Enrich Russians Who Enable Mass Atrocities in Syria
The rebellion, say many Congolese, is a Tutsi one, not involving them.
Nkunda, a Tutsi and former Congolese army general, has repeatedly blamed the Congolese government for not protecting Tutsis from Rwandan Hutus in Congo.
CNN: U.N.: Gunmen kill woman while trying to rape girl at camp
The Rwandan court has left cases against supporters of the current Tutsi-led government of Paul Kagame until last and these will prove hard.
ECONOMIST: The worst crimes, the law and the UN Security Council
The president of Congo, Joseph Kabila, for his part, is unhappy at the continued links between Mr Nkunda and the Tutsi-dominated Rwandan government.
Under the power-sharing deal, Tutsi President Pierre Buyoya is due to swap places with his Hutu Vice-President Domitien Ndayizeye on 1 May 2003.
Under a power-sharing deal signed in August, the Tutsi minority will have 40% of government and national assembly posts, compared to 60% for Hutus.
In the early 1990s ethnic Tutsi rebels from both sides of the border had fought the Hutu-led Rwandan government, which was supported by Mobutu.
This could bring them into the Hutu-Tutsi wars, on different sides.
ECONOMIST: The Hutu-Tutsi divide: Spreading poison in the Great Lakes | The
The 2005 vote was one of the final steps in a peace process intended to end years of fighting between Hutu rebels and the Tutsi-controlled army.
Mr Annan warned the Security Council that Burundi's Tutsi elite and the Hutu majority were "locked in implacable hostility to one another" with steadily rising violence.
The National Alliance for Change brings together the two former presidents Mr Buyoya deposed, Jean-Baptiste Bagaza and Sylvestre Ntibantunganya, one a Tutsi and one a Hutu.
Laurent Nkunda, the Congolese Tutsi general who leads troops of the National Congress for the Defense of the People, ordered the cease-fire, Ambassador Jean-Maurice Ripert told reporters.
Over the weekend the rebels, who say they are protecting the area's Tutsi minority, captured a major army camp at Rumangabo and the headquarters of Virunga national park.
Fighting in eastern Zaire between Tutsi-dominated rebels and Zairian troops has displaced more than one million Rwandan and Burundian refugees and left them cut off from international assistance.
But it is probably true that the group has no shortage of recruits, including disgruntled Hutus in Rwanda, whose government is led by a tough Tutsi, Paul Kagame.
France believes Tutsi rebels led by Mr Kagame were responsible for killing Mr Habyarimana because, they say, he was close to signing a peace deal with the rebels.
ECONOMIST: The arrest of a senior Rwandan official causes a storm
An ethnic Tutsi, he was Rwanda's main man in Congo.
ECONOMIST: Congo and Rwanda: Stop messing each other up | The
应用推荐