Four people have died of gunshot wounds in the southern Ethiopian city of Hawassa, where protesters have been demanding the establishment of a breakaway state, a hospital executive said Friday.
Security forces carried out arrests as violence spread to districts outside the regional capital on a second day of protests, state media reported.
The Sidama, the largest ethnic group in the southern region, have been agitating for their own semi-autonomous state, posing the latest political challenge to Prime Minister Abiy Ahmed.
Expectations had been high that they would unilaterally declare their own region on Thursday.
Ethiopia is already partitioned into nine semi-autonomous regions. The constitution requires the government to organise a referendum for any ethnic group that wants to form a new entity within a year of them requesting it.
The SLM, which has been leading calls for the new state, accepted government demands for a delay pending a plebiscite before the end of the year.
But other parties were unhappy and protests erupted Thursday.
Sidama activists have accused the security forces of opening fire on protesters who set tyres alight and lobbed stones on Thursday.
"There are four people dead, three men and one woman," said Zinaw Serniso, general manager of the Hawassa Referral Hospital.
One of the victims had been shot in the head while another was shot in the stomach.
Three of the victims died on Thursday, while the fourth, a woman, was admitted and died on Friday from injuries believed to have been sustained the previous day.
Regional police commissioner Tewodros Woldemichael told state-affiliated Fana Broadcasting Corporate that police were arresting people who had participated in violence.
He acknowledged that unrest had spread outside the city.
"Efforts are underway to put under control the violence which started in Hawassa and later spread to the neighboring Sidama woredas (district)," he said.
Hawassa residents said the city was calm Friday but that protests and clashes with security forces continued on the outskirts.
Desalegne Mesa, a spokesman for the Sidama Liberation Movement, said party members in and around Hawassa had reported 19 deaths in total, though that number could not be independently verified.
Desalegne called on the government to reduce the security presence in the Sidama region.
In addition to regional and federal police, soldiers from the Ethiopian military have been patrolling the streets of Hawassa. It is unclear who has been shooting protesters.
"The community is angry because of the delays of the government to answer their constitutional question," Desalegne said.
"The community has to remain stable and tolerant, and we'll see what the government does to solve this problem in a constitutional way. It's not good to solve problems by force."
Tessema Elias, a law professor at Hawassa University and an activist pushing for the formation of a new state, said a group of around five prominent Sidama activists had been arrested Friday.
He said the activists had been trying to convene a meeting to calm the population, and warned that their arrests could exacerbate tensions.
"There is a lot of misinformation going around," Tessema said. "People are not informed and there are a lot of exaggerations. I am getting a lot of reports of very brutal killings but I cannot give an exact number."
The Sidama issue is the latest headache for Abiy.
He has gained high marks abroad for his drive to reform the nation after decades of iron-fisted rule.
But change in this highly diverse country has also helped to fuel ethnic violence, displacing more than two million people.