Ethiopian state media are reporting that a military helicopter has crashed and killed all 18 people on board, including two children.
The aircraft crashed on a flight between the eastern city of Dire Dawa and Bishoftu in the centre of the country, the agency said.
Everyone on board – 15 soldiers and three civilians – were killed.
Police official Aschalew Alemu told the Ethiopian News Agency that the crash occurred on Thursday morning in the Oromia region.
The helicopter was travelling from the eastern city of Dire Dawa to an air base in Bishoftu town southeast of the capital Addis Ababa.
Mr Aschalew said the cause of the crash is under investigation.
The state-affiliated Fana Broadcasting Corporate reported that 15 military personnel and three civilians are dead.