The chief of staff of the Ethiopian army, Gen Seare Mekonnen, has been shot dead in the capital, Addis Ababa, state media confirm.
He and another officer died trying to prevent a coup attempt against the administration in Ethiopia's northern Amhara region, PM Abiy Ahmed said.In Amhara itself, the regional governor, Ambachew Mekonnen, was killed along with an adviser.
Ethnic violence has hit Amhara and other regions in recent years.
The prime minister went on TV dressed in military fatigues to denounce the attacks.
Since his election last year, Mr Abiy has moved to end political repression by releasing political prisoners, removing bans on political parties and prosecuting officials accused of human rights abuses.
The US state department has warned its staff in Addis Ababa to stay inside, saying it is aware of reports of gunfire in the city on Saturday.