Alexei Navalny moved to hospital as fears grow for life of Putin critic

Doctors say opposition leader, who is on hunger strike, is in danger of a heart attack or kidney failure

Alexei Navalny has been transferred to a prison hospital as concerns have grown among supporters that the opposition leader is dangerously ill and could die at any minute".

Navalny's transfer came after his doctors released paperwork showing that the Kremlin critic, who has been on hunger strike for nearly three weeks, said he was in danger of a heart attack or kidney failure.