U.N. Secretary-General Ban Ki-moon on Friday condemned the killing of a Nigerian peacekeeper with the joint African Union and U.N. peacekeeping force in the Darfur region of Sudan. “The secretary-general is appalled and saddened by the fatal shooting of a Nigerian UNAMID peacekeeper by unidentified armed assailants during an attack today on a UNAMID military position in Muhajeria, East Darfur," Ban's office said in a statement. “Two peacekeepers were also injured in the incident," the statement said. “[Ban] condemns in the strongest terms those responsible for the attack and calls on the authorities to immediately hold the perpetrators criminally accountable."