Six doctors from the Navalny-backed Alliance of Doctors have been detained in front of the prison in Pokrov where Russian opposition leader Alexei Navalny is now imprisoned.
Reuters reported that Anastasiya Vasilyeva, who is an ally of Navalny and leads a doctors' union, was detained after she was turned away from the prison, where she said she had an appointment with a senior prison official and that she wanted to see Navalny to check on his health.
Mr Navalny went on hunger strike last week, protesting against the prison administration's repeated refusals to let him see a civilian doctor or receive medication from his family after reporting searing pain in his back and legs.
After a brief standoff, the doctors and several protesters were arrested by local police, citing security concerns.
A Russian court ordered Navalny in February to serve 2½ years in prison for violating the terms of his probation, including when he was convalescing in Germany, from a 2014 embezzlement conviction. "I'm fully on his side", said Antonina Romanova, a Navalny supporter outside the prison.
TikTok came into the view of the authorities more recently after videos on the platform in January calling for Russians to join rallies in support of Navalny garnered hundreds of thousands of views.
"He looks bad, he's not feeling well, ' lawyer Olga Mikhailova told AFP, adding Navalny now weighs 'around 176 pounds".
Human rights group Amnesty International said Wednesday that Navalny is incarcerated in conditions that amount to torture and may slowly be killing him.
Last week, Russia's prison service denied Navalny's allegations that he was not receiving proper treatment, saying he had been given "all the necessary medical assistance in accordance with his medical indications".
Earlier this week, Navalny, 44, was moved to a sick ward in the prison in the town of Pokrov with symptoms of a respiratory illness.
Navalny said Monday that three of the 15 people he is housed with have been diagnosed with tuberculosis, a contagious disease that spreads through the air. He had complained of a persistent cough and temperature.
Mikhailova said Wednesday that Navalny's fever had lowered, but he is still coughing and is weak from the hunger strike. She said some 2,000 doctors had already signed an open letter demanding Navalny be examined by specialists he trusts, including from the German clinic that treated him after his poisoning.