Kremlin critic Vladimir Kara-Murza has been transferred to a prison hospital and his lawyers have been denied access to him for two days, his wife said on Friday, raising fears for the dissident's fate.
Kara-Murza, 42, is serving a 25-year prison sentence on treason and other charges, one of the harshest punishments Moscow has meted out to opponents of Russian President Vladimir Putin.
Twice poisoned in what he alleges were assassination attempts by the Russian security services, concern has grown for Kara-Murza's health since the death of opposition leader Alexei Navalny in an Arctic prison colony in February.
"Vladimir Kara-Murza was transferred to a prison hospital. His lawyers weren't allowed access to him," Evgenia Kara-Murza said in a social media post, adding that she had no information on his condition.
She said her husband had been transferred from the IK-6 high-security prison colony in the Siberian region of Omsk where he is serving his sentence to a regional prison hospital.
"His lawyers, who had travelled to IK-6 from Moscow and had been waiting from 8:30 in the morning on Thursday, were informed about this in the afternoon after more than five hours of waiting," she said.
After travelling to the hospital, they were first told Kara-Murza was not there, and then after visiting hours closed the facility confirmed to them he had been admitted.
Staff there continued to deny access to his lawyers on Friday, saying he had not been fully processed and was then being seen by doctors, Evgenia Kara-Murza said.
"Thus, the lawyers were not able to see Vladimir and make sure that he was alright," she said.
They may not be able to try again until after the weekend, she added.
Kara-Murza vocally campaigned against Putin for years, and stayed inside the country to criticise the military offensive on Ukraine even as Moscow passed a raft of anti-dissent and military censorship laws.
Hundreds have been prosecuted under the measures and most Russian opposition figures not in jail have fled into exile.
The Kremlin critic -- who is a dual Russian-UK citizen -- suffers from nerve disease after he fell severely ill in 2015 and 2017 in what he says were poisonings orchestrated by Russia's FSB security service.
An investigation led by Bellingcat journalists in 2021 also suggested that FSB agents were involved in both cases.
He was arrested in April 2022 and sentenced a year later after blasting Russia's military offensive on Ukraine and pressing Western countries to impose sanctions against the Kremlin.
From behind bars he has continued to campaign against Putin and urged Moscow to investigate his claims of having been poisoned.
His health is feared to have deteriorated in prison, where he is kept in harsh conditions and medical care is limited.
Since the death of Navalny -- for which Russian authorities have still not offered a full explanation -- concerns have risen over the fate of other Kremlin critics behind bars.
Russian opposition figure, Ilya Yashin, himself in jail, said he was "particularly" worried about Kara-Murza in a letter passed to his lawyers shortly after Navalny died.
"Vladimir Kara-Murza must be saved. The threat to his life is not just real, it is dire," Yashin said in February, pressing Western diplomats to try to secure his release.
