An International Criminal Court appeals chamber has upheld a ruling to drop war crimes charges against a Rwandan man.

Callixte Mbarushimana faced eight counts of war crimes and five counts of crimes against humanity in connection with the rape, murder, and torture of civilians in the eastern Democratic Republic of Congo.

But ICC judges ordered Mbarushimana's release in December, saying there was not enough evidence to show he could be held criminally responsible.

The appeals court on Wednesday upheld that decision, dismissing a challenge from prosecutors.

The prosecution said Mbarushimana was a top leader of a rebel group, the Democratic Forces for the Liberation of Rwanda, or FDLR.

The group, based in the eastern DRC, attacked civilians in Congo's North and South Kivu provinces in 2009.

The FDLR was established by ethnic Hutus who took part in the 1994 Rwandan genocide of Tutsis and fled to Congo after the killing spree was stopped.

French authorities arrested Mbarushimana in Paris last year on an ICC warrant. He had received refugee status in France in 2003.