More than 80 civilians died in the latest attack in an area of western Ethiopia that has seen recurring grisly violence in recent months, the national human rights commission said Wednesday.

The killings are likely to ramp up pressure on Prime Minister Abiy Ahmed, the 2019 Nobel Peace Prize winner, to intervene more forcefully in the region of Benishangul-Gumuz, which borders Sudan and South Sudan and is home to a massive hydropower project on the Blue Nile River. 

"We've received information that over 80 civilians were killed on January 12 in an area called Daletti" in the Metekel zone of Benishangul-Gumuz, Aaron Maasho, an advisor and spokesman for the Ethiopian Human Rights Commission (EHRC), told AFP.

Hundreds of civilians in Metekel have been killed by assailants using guns, knives and other weapons in attacks going back to at least September.

Some 207 people were killed in one attack on December 23 alone.

Abiy has so far struggled to impose order in Metekel or explain what is driving the violence, despite visiting the area in December and empowering a command post to take charge of security there. 

There is no known link between the violence and military operations in Ethiopia's northernmost Tigray region, where Abiy sent in troops in November to detain and disarm leaders of the dissident regional ruling party. 

Tuesday's attack in Metekel occurred between 5 and 7 am, with victims ranging in age from two to 45, Aaron said. 

The EHRC, a government-affiliated but independent body, is "still chasing further details about the perpetrators" and how the victims were killed, he said. 

One survivor, Ahmed Yimam, told AFP Wednesday he had counted 82 bodies and said 22 people were injured. 

"The attack was carried out mostly using knives although arrows and firearms were also used," he said. 

"I fear more attacks as the perpetrators aren't receiving punishment, and there is no functioning government at local and regional level," he said. 

Grim attacks

Addressing lawmakers in October, Abiy said fighters active in Metekel were receiving training and shelter in neighbouring Sudan -- though he provided no evidence -- and that Khartoum's assistance was needed to stabilise the area.

Ethiopian opposition politicians have described the violence in Metekel as ethnically motivated, alleging a targeted campaign by ethnic Gumuz militias against members of other ethnic groups in the area, including the Amhara, Ethiopia's second-largest group.

Dessalegn Chanie, a senior member of the National Movement for Amhara, an opposition political party, told AFP Wednesday that he suspected at least some local officials were cooperating with the assailants. 

"The problem is much more complicated because a lot of Gumuz cadres are supporting this militia. They provide logistics, they provide information," he said. 

He did not give evidence to back up his claim, though several officials in Benishangul-Gumuz were arrested in December over their alleged roles in violence that month.

Dessalegn said his sources in Benishangul-Gumuz, including hospital officials, had informed him that at least 131 people were killed in this week's attack and that the figure was likely to rise.

On Monday, state-affiliated Fana Broadcasting Corporate reported that "relative peace has been restored in Metekel" because of the government's response to the violence, but the EHRC's Aaron said Wednesday that more needed to be done.

"These civilians have barely had a respite from such grim attacks for months. We once again call on federal and regional authorities to enhance their coordination when responding to such incidents to prevent the loss of life in Benishangul-Gumuz," he said. 

"We remind the authorities that the protection of civilians is the primary duty of the government."