Rwanda's National Commission for the Fight against Genocide (CNLG) on Friday described as a "landmark" the conviction of a former Rwandan official by the Brussels High Court on Thursday for genocide and war crimes.

Fabien Neretse, 71, was sentenced on Friday to 25 years in prison by the Belgian court following Thursday's conviction.

He was prosecuted for genocide and war crimes committed during the three-month Rwandan genocide against Tutsi minority in 1994, which claimed the lives of over 1 million people.

Neretse, who denied all charges during the trial, is the first person to be convicted in Belgium on a genocide charge, said the CNLG in a statement.

Magistrates of Belgium had been compiling evidence of the case over the years since Neretse was arrested in France in 2011.