The Australian Defence Force (ADF) is investigating claims of misconduct by Australian special forces in a mission in Afghanistan which resulted in the death of four insurgents. Defence force chief General David Hurley said it related to a combined operation between Afghan National Security Forces (ANSF) and Australia's Special Operations Task Group (SOTG) in Zabul province on April 28. "An incident of potential misconduct during the operation has been raised through the internal national command chain," he said in a statement. General Hurley said this was being investigated by the ADF in co-operation with International Security Assistance Force. This mission was directed at an insurgent commander responsible for a key insurgent network operating in and around Oruzgan province. "During the course of clearing the targeted area, the force element positively identified several armed insurgents moving to gain a tactical advantage and due to the threat posed, the combined ANSF and SOTG force element engaged and killed four insurgents," he said. General Hurley said Defence would not comment further on the matter until the investigation was completed.