Ukraine's human rights ombudswoman has said she was not allowed to visit Ukrainian film-maker Oleg Sentsov, jailed in Russia on terror charges.
Prison officials said this was because "Sentsov is a Russian citizen", Lyudmyla Denisova told the BBC.
Sentsov has been on hunger strike for 33 days to push for the release of what he says are 64 political prisoners in Russia - a claim denied by the Kremlin.
In 2015, he was jailed for 20 years for plotting terrorist acts in Crimea.
During the trial he denied the charges, saying that "a court of occupiers cannot be just".
Russia annexed Ukraine's southern Crimea peninsula in 2014, triggering condemnation from many countries.
The annexation and Russia's support of rebels in eastern Ukraine led to a series of sanctions imposed by Western nations against Moscow.
What did Ukraine's ombudswoman say?
Ms Denisova said she had flown to Russia's northern town of Salekhard and tried to visit the prison where Sentsov is being held.
"We were told categorically that we wouldn't be allowed to see Oleg Sentsov," she told the BBC.
"I asked why and he [the head of regional prisons department] said 'because Sentsov is a Russian citizen so I took this decision.'
'We are very concerned about his health as we have no confirmed information that he is OK, and we can't trust the information provided by the Russian side," Ms Denisova added.
She said the idea of her visiting Ukrainian prisoners in Russia had been agreed following a phone call between Ukrainian President Poroshenko and his Russian counterpart Vladimir Putin last week.
Meanwhile, Russia's human rights ombudswoman was expected to travel to Ukraine to visit Kyrylo Vyshynsky, a Ukrainian-Russian journalist accused of treason. Mr Vyshynsky denies the charges.
Ukrainians have been staging protests near Russian embassies around the world, demanding the release of Sentsov and other Ukrainian prisoners in Russia.
Many activists have also been calling for the boycott of the football World Cup currently being held in Russia.
Allegations of torture
Sentsov, best known for his 2011 film Gamer, was accused of setting up a terrorist group. Prosecutors say he was involved in two attempted arson attacks in the city of Simferopol, ordered by extremist Ukrainian group Right Sector.
The Ukrainian government says he is being punished for being a Crimea-based pro-Ukrainian activist.
The director has said he was beaten in jail for 24 hours in an attempt to force a confession.
But investigators refused to open a case into his allegations of torture, suggesting that his bruises were self-inflicted and that he was keen on sado-masochism, his lawyer said.
- 25 September 2017
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