At least 29 civilians were killed over the weekend by the rebel Oromo Liberation Front (OLF) in Debis and other three localities in the Horo Gudru zone of Ethiopia's restive Oromia region, APA reports citing APN.
OLF Shene entered the Ethiopian church in Debis locality and shot dead the head of the church.
They took hostage 28 believers but later killed them in nearby a jungle, relatives of the victims told local media.
The relatives also told journalists that bodies of the victims were recovered on Sunday and laid to rest in the same locality.
Residents of the districts were quoted as saying that the security gap was created as the militia in the district and Oromo regional state Special Forces were deployed to another area.
The residents claimed the attackers were backed by the local leadership whose members were also accused of participating in the massacre.
The Oromo Liberation Front gunmen had information about the security vacuum, the residents have said.