Ethiopian youths in the capital and other cities protested against the killing of a popular singer, Haacaaluu Hundeessaa.
Six people died on their way to hospital and two died in intensive care, said Dr Mekonnen Feyissa, the medical director of Adama’s main hospital.
The hospital received around 80 injured patients, he said. Most had been shot but some had been hit with rocks or stabbed.
Adama is about 90 km (56 miles) southeast of the capital, Addis Ababa
The unrest had jeopardised Prime Minister Abiy Ahmed’s power base in his ethnic heartland.
Abiy called for calm following the killing of the musician whose political songs were the soundtrack of the protest movement that propelled Abiy to power two years ago. In a tweet, Abiy offered condolences and promised an investigation.
Dr Mekonnen Feyissa, medical director of the main hospital in the town of Adama, said the hospital had received around 80 wounded patients.
Most had been shot but some had been hit with rocks or stabbed. Six died en route to the hospital and two died in intensive care.
The prime minister and the slain singer are both from the Oromo ethnic group, Ethiopia’s largest, which has long complained of being marginalised by national leaders from other communities.
Other pictures appeared to show demonstrators pulling down and beheading a statue of former emperor Haile Selassie’s father in the Oromo city of Harar. Reuters could not verify the authenticity of the pictures or video.