The Sudanese government was assured by the African Union (AU) that Darfur rebels have violated the ceasefire by opening fire on the military envoy, Foreign Minister Mostafa Othman Ismael said here on Monday. Speaking at a news conference, Ismael said the AU's representative here told him that the rebels opened fire at the Sudanese military envoy. The representative also said that he has some information that prove that incident, but the African Union is currently investigating the attack further.The Sudanese government and rebel groups traded charges yesterday on violating the previously-signed ceasefire agreement last April. The rebel Sudan Liberation Movement accused government troops backed by helicopters, of bombing villages in south Darfur on Friday and Sunday.