A Norwegian court has convicted a Rwandan man living in Norway for participating in the 1994 genocide in his home country and sentenced him to 21 years in prison.

The Oslo district court found Sadi Bugingo, 47, guilty of complicity in the premeditated killings of at least 2,000 people belonging mainly to the Tutsi ethnic group. It singled out three prolonged attacks in his home town of Kibungo, eastern Rwanda, during April 1994.

Bugingo has denied all charges and said he would appeal.

The court said that the former businessman participated in the massacres and organised them by transporting armed killers and victims to the sites of the killings.

"Several witnesses have described how the accused was present in the massacres," Judge Jonas Petter Madsoe said. "In this court's view, there are also several other circumstances in the case which together support the conclusion that the defendant supported and participated in the genocide which took place in Kibungo."

During his defence Bugingo claimed that he was not in the region at the time of the massacres and said he had not known about them.

Madsoe noted that he had been a wealthy local businessman and found his claims "not credible".

Bugingo arrived in Norway in 2001 to join his family who had fled from Rwanda some years earlier. He was granted a residence permit in 2005 and worked as a cleaner in the western city of Bergen until he was arrested in 2011.

The 19-week trial was the first genocide case in a Norwegian court. Similar cases against Rwandans have been brought in neighbouring Sweden, Finland and Denmark.

More than 500,000 people were killed in the 1994 Rwanda genocide that was carried out by Hutu extremists against the Tutsi minority and Hutu moderates.