Russian government has moved jailed Kremlin critic Alexei Navalny has been moved to a prisoners hospital from the penal colony he has been kept, as concerns over his health mount.

According to a statement by Russia’s Federal Penitentiary Service (FSIN) quoted by CNN, Navalny had been moved to a hospital specializing in “dynamic” observation of patients.

The hospital is located in another penal colony in the Vladimir region, CNN report said.

Also read: Russia rejects foreign concerns over Alexei Navalny’s health

The statement describes Navalny in “satisfactory condition” and says that the leader has been put on “vitamin therapy with his consent”.

His supporters have criticised the choice of hospital that he has been shifted to. “This is where seriously ill patients are transferred,” CNN quoted Ivan Zhdanov, the director of Navalny’s Anti-Corruption Foundation, as saying.

Navalny has been on a hunger strike since March 31, demanding “proper medical care” and to be examined by independent doctors.

According to his supporters, Navalny’s condition is rapidly deteriorating and “he could die in a matter of days.”