Cluster Bombs found in South Kordofan KHARTOUM, Sudan, May 25 (UPI) -- Unexploded cluster bombs were found in South Kordofan where the Sudanese army is fighting the rebel Sudan People's Liberation Movement-North, officials said. The Sudan Tribune reported Friday remnants of the tail section of an RBK-500 AO-2.5RT cluster bomb was found near the village of Ongolo in southern Sudan. A similar discovery was made in nearby Nuba, the report said. Villagers told the Sudan Tribune the bombs had been dropped by a Sudanese warplane April 15. Human Rights Watch urged the Sudanese government in a statement Wednesday to investigate "the discovery of cluster bombs in the restive region," calling for Khartoum to join an international treaty banning the devices. Sudan denied any bombs had been found, saying it has no such munitions.