The former cabinet director in Rwanda's defence ministry at the time and a colonel, pleaded not guilty. Over 800,000 people died within the space of just 100 days during the genocide.

According to the indictment at the International Criminal Tribunal for Rwanda (ICTR), based in Tanzania, Bagosora and three former senior military officers all conspired to "work out a plan with intent to exterminate the civilian Tutsi population and eliminate members of the opposition," the BBC reported.

This is the first time the Rwanda tribunal has convicted anyone of actually organising the killings.  In its first verdict on Thursday, the Rwandan court sentenced Protais Zigiranyirazo, 57, to 20 years in jail for his part in the genocide. Zigiranyirazo, a brother-in-law of former President Juvenal Habyarimana, was accused of ordering Hutus to kill 48 people in two incidents.

Bagosora, 67, has been in custody since 1996, when he was arrested in Cameroon.

He faces 11 charges of genocide, war crimes and crimes against humanity. The prosecution says he played a key role in plotting to exterminate the Tutsis and moderate Hutus, and that he also set up the Interahamwe - gangs of Hutu extremists who carried out much of the slaughter.

Prosecutors say Bagosora assumed control of military and political affairs in Rwanda when President Habyarimana's plane was shot down in 1994 - the catalyst for the genocide. He is said to have distributed the arms and machetes that became the chief tools of the genocide.

The indictment alleges that he set out to "prepare the apocalypse" as far back as 1990.

The following year, Bagosora helped draft a document circulated within the army that described Tutsis as "the principal enemy".

Canadian General Romeo Dallaire, head of UN peacekeepers in Rwanda at the time, described Bagosora as the "kingpin" behind the genocide and said the colonel had threatened to kill him with a pistol. His defence says there is no hard evidence to link him to the deaths of hundreds of thousands of Rwandans.

Bagosora's lawyer has also challenged the basis for the case, arguing that prosecutors failed to prove that the slaughter was organised and therefore failed to prove that it met the legal definition of "genocide".

The trial, which began in 2002, was expected to last two years. The effects of the genocide are still being felt in the region, in particular across the border in DR Congo.

Some of the Hutu militias involved in the genocide fled to DR Congo, where Tutsi rebels, allegedly with some Rwandan backing, refuse to lay down their arms, saying they are being attacked by the Hutu fighters.