Belarusians are protesting the death of Roman Bondarenko, a vocal critic of President Alexander Lukashenko.
The 31-year-old military veteran had been arrested and died in police custody.
Bondarenko was brutalized by plainclothes police officers in Minsk.
He was attacked during an argument over ribbons that depict support for anti-government protests.
The children’s art teacher reportedly hit his head on the ground and was hauled off by the security operatives.
Bondarenko later fell into a coma in a hospital. He died last Thursday due to brain damage.
The Viasna human rights organisation said nearly 1,000 demonstrators have been arrested nationwide.
Former presidential candidate, Svetlana Tikhanovskaya, stated that Bondarenko was killed by “accomplices of the regime”.
He noted the deceased was a victim of an inhumane system that considers people’s lives to be the cost of power.
“We all understand that any peaceful person could have ended up in his place”, Tikhanovskaya wrote.
The European Union (EU) is furious about the death and has threatened to impose further sanctions against the government.
“This is an outrageous and shameful result of the actions by the Belarusian authorities who have not only directly and violently carried out repression of their own population, but also created an environment whereby such lawless, violent acts can take place,” The Guardian quoted a spokesman.
EU only just slammed a travel ban and asset freeze against Lukashenko, his son Viktor and 13 officials for “violent repression and intimidation of peaceful demonstrators”.
In recent weeks, there have been protests against police brutality in Angola, Nigeria, Peru, Uganda, among other countries.