Gunmen killed at least 20 people last week in western Ethiopia, a regional government official said on Thursday, in what he and two residents described as an attack on civilians from the Amhara ethnic group.
The incident occurred in the district of Limmu Kosa, in the Jimma zone of the Oromiya region.
At least 20 civilians were killed in the attack, the Oromiya regional government's spokesman Getachew Balcha told Reuters. He said the attackers were from OLF-Shane or Oromo Liberation Army (OLA), a splinter group of the Oromo Liberation Front (OLF), a formerly banned opposition group that returned from exile after Prime Minister Abiy Ahmed took office.
The Oromo are the country's largest ethnic group and the Amhara are its second largest. Clashes between people from the two groups killed 18 people in another part of the country earlier this month.
The Amhara and Oromiya regions share a border and attacks between the two ethnic groups in border areas have been rising in recent months.
Political and ethnic violence is a major challenge for Abiy, whose political reforms have also encouraged regional powerbrokers seeking to build ethnic power bases after nearly three decades of iron-fisted government.
Two residents also told Reuters that gunmen targeted Amhara residents in last week's attack.
"I was outside when the armed men came to our village and they started to kill residents and burn houses," said one of the residents, who spoke on condition of anonymity for fear of reprisals.
He said he and neighbours buried 29 people, mostly killed by gunfire, and a few from machete wounds.
That resident also identified the attackers as being from OLF-Shane.
A spokesman for the OLA, Odaa Tarbii, denied the accusation in an emailed comment, and accused the regional forces from the Oromiya region of being responsible for the attack.
He said state security forces left the area, enabling "government-affiliated militiamen" who were not the OLA to storm the area and target and kill Amharas.
The other resident said local security forces did nothing to stop the killings, as armed men went from house to house killing residents. He also said that some of the attackers wore a uniform similar to those used by federal troops.
Ethiopia’s state-run human rights commission said on Saturday that it was monitoring reports of an attack by armed groups in the Limmu Kosa area and that "civilian casualties have already been reported".