A court has sentenced Rwanda's former army chief to 30 years in prison for ordering killings during the 1994 genocide.

The International Criminal Tribunal for Rwanda sentenced Maj. Gen. Augustin Bizimungu on Tuesday along with three other top officers.

Presiding Judge Asoka de Silva said Bizimungu was responsible for the conduct of his subordinates.

The indictment against Bizimungu says he gave an order "to exterminate the small cockroaches" on the first day of the genocide.

At least 500,000 ethnic Tutsis and moderate Hutus were slaughtered during the 100-day genocide in 1994. Bizimungu was captured in Angola in 2002.