Jailed Kremlin critic Alexei Navalny has said he has a persistent cough and temperature.
He added that there have been cases of tuberculosis in his prison.
It was gathered that the 44 year old Alexei Navalny had been transferred to a medical unit with symptoms of a respiratory illness.
Navalny’s Lawyer said he was in a bad way, lost a lot of weight and declared a hunger strike last week.
He is being held at a penal colony to serve out a sentence for embezzlement.
The conviction was widely seen as politically motivated, as supporters of Navalny said they are planning to hold a protest at the colony.