At least 25 people have died in clashes between Ethiopian security forces and activists in southern Ethiopia, hospital officials have told the BBC.
The officials said security forces fired bullets during the protests across the Sidama region.
Activists from the Sidama ethnic group were set to declare their own federal state on Thursday.
They accused the government of failing to hold a promised referendum on the issue.
The Sidama are Ethiopia's fifth biggest ethnic group, making up 4% of the population and are mainly based in the state known as the Southern Nations, Nationalities and Peoples' Region (SNNPR).
The four bigger communities all have their own regions within Ethiopia's ethnically based federal system.
Reports from activists and opposition groups cite a higher death toll with fatalities as high as 60, but the local acting security head, Andinet Ashenafi, warns against what he called exaggerated numbers, reports the BBC's Kalkidan Yibeltal from Addis Ababa.
Mr Andinet confirmed to the BBC that four people had been killed in the city of Awassa and 26 others sustained wounds.
Members of other ethnic groups were also killed after being attacked by angry mobs.
Local media reported that protesters had attacked a tourist lodge, leading to 12 tourists being escorted out by troops.
The internet has been blocked in parts of the south of the country since Thursday, including the main city of Hawassa.
What started the protests?
Shortly after Ethiopia's Prime Minister Abiy Ahmed came into power last year, promising sweeping democratic reforms, Sidama activists submitted their request for a referendum on having their own officially recognised region.
As part of the constitution, the Ethiopian government must hold a referendum within a year of a request from any ethnic group which wishes to form a separate entity.
The deadline for the Sidama referendum was Thursday 18 July, but after a complex period of transition following Mr Abiy's first year of leadership, as well as a wave of ethnic tensions and an alleged regional coup, the government did not organise the vote in time.
The Sidama announced they would declare their own federal state on the deadline for the referendum: Thursday 18 July.
Large-scale violence was avoided as Sidama opposition groups agreed with the government to delay the declaration and hold a referendum in five months.
But for some Sidama people, this compromise was not enough, resulting in the protests and violence.
Why do the Sidama ethnic group want their own region?
As the fifth largest ethnic group in Ethiopia, the Sidama want the same level of autonomy as the four larger communities.
Most Sidama people are farmers and coffee is a particularly prominent source of income.
If the Sidama get their own region, it would mean the regional government could pass policies to suit their economic and cultural needs.