Witnesses to the outbreak of ethnic violence in western Ethiopia told the BBC they were helpless in the attack that left more than 250 dead.
One man said he and other villagers buried around 250 bodies, including those of his brother and sister-in-law.
The figures have not been independently verified, but other witnesses have offered similar accounts.
The victims are said to be Amharic.
The Oromo Liberation Army (OLA) denied responsibility and said the government’s “retreat soldiers” were behind the attack. A spokesman further blamed militias formed by the Oromia regional government.
According to eyewitnesses, the attack took place in six small villages in the Kimbi district of western Oromia state.
Attempts by the BBC to obtain more information from local officials and Oromia region spokesmen were unsuccessful.
The area has recently seen fighting between government forces and the OLA. The Ethiopian Human Rights Commission, the Ethiopian government’s rights watchdog, said the attacks could be linked to that fight.
A man, whose 16-year-old daughter was also among the dead, said: “I was told that the village was full of corpses.”
The attack reportedly started around 09:00 on Saturday and continued until around 13:00. Residents said they immediately called regional authorities but only received help hours later.
“[Regional] Special forces and troops arrived around 5pm. No one came to help us until then,” one resident said.
The Amhara Society of America, an advocacy group, put the death toll at 378 and said 176 victims had been named.
Another witness told the BBC that in addition to those killed on the spot, some people were kidnapped by the attackers.
“After they took them, they killed them in the woods. 50 bodies were found in the forest,” he said.
“They went into the houses of Amharic speakers and started killing people,” he continued.
He added that in the village of Gutu, eight people had their houses burned and another 35 people were buried in the village, while in the village of Silsaw, 102 people were buried.
For their own safety, the BBC did not name the witnesses used in this report.
Ethiopian Prime Minister Abiy Ahmed called the violence unacceptable.
“We have zero tolerance for the recent horrific actions that have taken lives in Benin’s Shangour and Oromia regions by elements whose main goal is to terrorize the community,” Mr Abbey tweeted.
“Restoring peace and security to affected communities remains our top priority,” he continued.
Over the past three years, Ethiopia has seen an unprecedented increase in ethnic violence, killing thousands and forcing millions from their homes.
The country has also been ravaged by civil war in northern Tigray since November 2020.