Hundreds of civilians were killed in an attack in Ethiopia's western Oromia region, witnesses who declined to give their names saying they feared reprisals said on Monday.

On Saturday, gunmen in the Gimbi district of Western Wollega Zone allegedly launched an attack on ethnic Amharas — a minority in the region. It appears to be one of the country's deadliest incidents in recent years.

Witnesses reported death tolls ranging from 260 to 351 people.

Survivors of the attack, as well as the state-appointed human rights commission and regional authorities, blamed it on ethnic Oromos from a group called the Oromo Liberation Army (OLA).

The OLA is designated as a terrorist organization by the central government, having splintered off from the Oromo Liberation Front, a once-banned opposition group that returned from exile after Prime Minister Abiy Ahmed took office in 2018.

Last year, the OLA formed an alliance with the Tigray People's Liberation Front (TPLF), which has been waging war against the federal government in the country's north.  

"The intention of all these attacks is to force us to leave," one survivor told the AFP news agency said, adding that "our houses and properties have been destroyed,"

"I want to leave this area, go to my ancestral region... that at least would allow me to live in peace," he said.

Another survivor told Reuters news agency that he survived by hiding in a ditch, but lost four siblings and three cousins in the attack.

The insurgent OLA group denied responsibility for the attack, blaming it on government forces.

The victims of Saturday's attacks have been buried in mass graves.

Prime Minister Abiy Ahmed, himself an Oromo, earlier condemned the "horrific acts."

"Attacks on innocent civilians and destruction of livelihoods by illegal and irregular forces is unacceptable," he said on Twitter.

Saturday's attack came just after days after the Ethiopian Human Rights Commission accused government security forces of summarily executing residents in the bordering region of Gambella, after forces accused the population of collaborating with OLA fighters.

aw/msh (Reuters, AFP)