( CNN ) -- Five Afghan policemen were killed as result of a U.S. airstrike , according to an International Security Assistance Force public information officer , who said the incident was an accident and is under investigation . The strike occurred amid a joint operation between Afghan National Security Forces and the ISAF in the Batikot area of Afghanistan , Tech Sgt . Peter Dean said . Dean would not release any additional details . The ISAF is a NATO-led security mission in Afghanistan . U.N. : Civilian casualties in Afghanistan up by nearly a quarter . From CNN 's Larry Register .
Deaths of police officers are being investigated , ISAF public information officer tells CNN . Afghan forces kill 10 Taliban in Helmand province, officials say. Dean would not give more details . The International Security Force is a NATO-led mission in Afghanistan .