A prosecutor at a U.N.-backed tribunal is accusing a Rwandan official of ordering the murder of children too weak to walk during the country's 1994 genocide.

Paul Ngarua says that suspect Callixte Nzabonimana used his position as Rwandan Minister for Youth to encourage the killings. Nzabonimana has pleaded innocent to five counts of genocide and related charges. His trial opened Monday.

More than 500,000 ethnic Tutsis and moderate Hutus were killed during the slaughter.

The U.N. court, set up in 1994 by the Security Council, has so far convicted 40 people and acquitted six. Trials are currently under way for 11 others.