The UN tribunal for Rwanda Tuesday handed a life sentence to a former army captain nicknamed the "Butcher of Butare" for his role in the 1994 genocide.

Ildephonse Nizeyimana is the last member of the former Rwandan army who will be tried by the International Criminal Tribunal for Rwanda.

Two other officers are still on the run, but if they are arrested they will be judged either by the Rwandan courts or by the smaller-scale legal mechanism that will take over from the ICTR.

"The court sentences Ildephonse Nizeyimana to life in prison," presiding judge Lee Gacuiga Muthoga said.

The three judges on the panel were unanimous in finding Nizeyimana guilty of genocide, crimes against humanity and war crimes. He was acquitted only of rape.

The crimes Nizeyimana was found guilty of were committed in April and May 1994 in the southern town of Butare where he was second-in-command of a military school.

The court found he was guilty of authorising or ordering several murders, notably that of Rosalie Gicanda, a traditional queen.

Nizeyimana, who was arrested in 2009 in Uganda, was also found responsible for the killing of "several thousand" Tutsis massacred by men from his training school at the parish of Cyahinda on April 18, 1994.

Nizeyimana's lawyer John Philpot said his client would appeal.

The ICTR, which was set up to try the masterminds behind the Rwandan genocide, plans to wind up its lower court cases this month and its appeals in 2014.