A Ukrainian activist was released from a penal colony in Russia on August 3, after serving more than four years.
Oleksandr Kostenko had been convicted by a court in Russia-annexed Crimea in 2015 for allegedly attacking security forces in Kyiv during protests in February 2014 in the Ukrainian capital against then-President Viktor Yanukovych, who was allied with the Kremlin.
Kostenko and his supporters said Russia had no right to put him on trial.
Russian authorities claimed jurisdiction, arguing one of the police officers allegedly injured by Kostenko had obtained Russian citizenship.
Moscow granted Russian citizenship to dozens of Ukrainian riot police officers who were involved in the deadly standoff with unarmed protesters in Kyiv during the Euromaidan protests.
Yana Goncharova of the RosUznik rights group posted photos of Kostenko after leaving the penal colony in the city of Kirovo-Chepetsk.
Goncharova said in June that Kostenko had been placed in solitary confinement ahead of his scheduled August release.
Goncharova also said Kostenko needed medical treatment for an arm that was broken during his arrest in 2015.
Russia occupied and annexed Crimea from Ukraine in March 2014, triggering sanctions by the United States and European Union and condemnation by some 100 countries at the United Nations.