Oromos have been the victims of indiscriminate and disproportionate attacks in the hands of security forces.
The UN human rights chief has urged Ethiopia to allow international observers to investigate the killings of 90 protesters in restive regions at the weekend.
Zeid Raad Al Hussein, UN High Commissioner for Human Rights, said on Wednesday that allegations of excessive use of force across the Oromia and Amhara regions must be probed and that his office was in discussions with Ethiopian authorities.
“The use of live ammunition against protesters in Oromia and Amhara of course would be a very serious concern for us,” Zeid told the Reuters news agency in an interview in Geneva.
He also said that his office had “not seen any genuine attempt at investigation and accountability” since January when the killings of protesters first began.
Unrest continued in Oromia for several months until early this year over plans to allocate farmland surrounding the regional capital for development.
Authorities in the Horn of Africa state scrapped the scheme in January, but protests flared again over the continued detention of opposition demonstrators.
In the weekend, protesters chanted anti-government slogans and waved dissident flags.
Some demanded the release of jailed opposition politicians. Information on the reported killings has been difficult to obtain, Zeid said.
He added that any detainee, who had been peacefully protesting, should be released promptly.
The state-run Ethiopian News Agency said on Monday that “illegal protests” by “anti-peace forces” had been brought under control. It did not mention casualties.