Russia's opposition politician Alexei Navalny, who's on hunger strike, had been transferred to a hospital for inmates, his lawyer confirmed on Monday.

He is now at a prison hospital at a penal colony in the town of Vladimir near Moscow, following a decision by Russia's prison authorities to transfer him earlier on Monday.

Navalny's lawyer, Alexei Liptser, said he was waiting at the penal colony to visit his client but had yet to be allowed in.

Prison authorities earlier said in a statement that doctors had "made a decision" to deliver Navalny to a medical facility on the premises of his penal colony outside Moscow and that he had agreed to take vitamin supplements as part of medical treatment.

The 44-year-old opposition politician's health had been in a satisfactory condition and he was being examined by a doctor on a daily basis, the authorities added.

Navalny, who has been in prison since February and is serving two-and-a-half years on embezzlement charges, started his hunger strike on March 31 to demand proper medical treatment after reporting back pain and numbness in his legs and hands while in detention.

His doctors previously said he is at risk of dying due to cardiac arrest as a result of the hunger strike.

(With input from Reuters and AFP)