Militia members from Ethiopia's second largest ethnic group killed dozens of people and torched and looted homes in an attack on a town in the country's restive Oromia region, survivors told AFP.
The regional authorities accuse the Oromo Liberation Army (OLA) of being behind the attack, the toll of which "has yet to be confirmed".
The attack took place early Monday in Agamsa in Oromia, Ethiopia's largest and most densely populated region which is regularly rocked by clashes between the Oromo and Amhara ethnic groups.
"The attackers attacked... from three directions using gunfire and continued their attacks until around 2:00 pm," a survivor, who fled Agamsa told AFP.
"They killed around 100 residents, torched many houses and shops and looted food warehouses using rickshaws, cars and motorcycles. I saw the attack with my own eyes, but managed to flee unharmed."
Another survivor said the assailants stole cattle and killed more than 100 people.
Both said the men were members of a militia based in the neighbouring Amhara region.
The Oromo Liberation Army (OLA), which is designated a terrorist organisation by Addis Ababa, said the Amhara Fano militia staged the attack and killed at least 62 people in Agamsa.
Oromia's regional authorities have blamed the OLA, which they call "Shane."
"What happened in Agamsa was that the Shane terrorist group and extremists attacked civilians. The number of victims has yet to be confirmed," Hailu Adugna, the regional government's communications chief, told AFP.
The federal government did not respond to AFP's request for confirmation.
Locals said the attack came after rotating regional troops left the area on Sunday but had not been replaced.
A resident, who fled Agamsa but returned, said: "I'm still in Agamsa town but there is no government security forces presence. We're afraid the attackers will come again."
In August last year, the Ethiopian Human Rights Commission said over 210 people were killed in a week of ethnic attacks in Gida-Kirimu, near Agamsa.
In June, hundreds of mainly Amhara civilians were killed in a restive area in the far west of the country.
Ethiopian Prime Minister Abiy Ahmed blamed the Oromo Liberation Army, saying it was "inflicting damage" on people as its fighters fled an offensive by security forces in western Oromia.
Officials have blamed the OLA for a number of massacres targeting Amharas, although the rebels have denied responsibility.