OVD-Info, which reports on freedom of assembly in Russia, quoted a relative as saying that Rifat Dautov had not taken part in demonstrations called to denounce the jailing of an activist defending the local language and culture.
Dautov was detained briefly in Ufa, chief town of the region in Russia's Urals mountains, on the day of a protest and later in a town to the south where he was taken away by a group of men identifying themselves as police.
Local authorities subsequently said he had died but granted his family no access to the morgue. OVD-Info quoted local media as saying Dautov fell ill while being transported to a courthouse and medics pronounced him dead.
Police used tear gas and batons to break up a demonstration in a small town in Bashkortostan to denounce the sentencing of activist Fail Alsynov to four years in a penal colony.
Hundreds attended a protest days later in Ufa in response to the jailing of Alsynov, regarded as a hero by many of the region's ethnic Bashkir people.
He led successful protests in 2020 to prevent mining operations on a hill that residents consider sacred, and has spoken out over the dispatching of local men to serve in the war in Ukraine.
Kremlin spokesperson Dmitry Peskov played down the significance of the protests, saying they could not be described as mass riots or disorder.
(Reporting by Ron Popeski, Editing by Franklin Paul)
