A 61-year-old Ukrainian, Kostyantyn Shyring, died in colony No 5 in the Russian city of Novotroitsk, Orenburg Region.
Earlier he was illegally sentenced to 12 years on charges of "espionage", the Crimean Human Rights Group (CHRG) has said, quoting its sources in the colony.
"According to human rights activists, Kostyantyn Shyring needed heart surgery, sought medical help, but the operation was never performed," the group said.
It is noted that there is currently no official confirmation of Shiring's death in colony No 5. Formally, an investigation will still be conducted.
CHRG head Olha Skrypnyk emphasized that the responsibility for Shyring's death lies with the colony administration. And the failure to provide medical care to our citizens in Russian prisons is a systemic practice.
In October 2021, the Russian-controlled "Supreme Court of Crimea" illegally sentenced 61-year-old Ukrainian Kostyantyn Shyring in a fabricated criminal case for alleged "espionage". He was sentenced to 12 years in prison to be served in a maximum-security colony.