Alexei Navalny is being sent to a hospital two days after his doctor warned that the opposition leader could be on the verge of death. Navalny’s physician, Yaroslav Ashikhmin, said Saturday that his condition has rapidly deteriorated during the third week of a prison hunger strike. The doctor said in a Facebook post that Navalny is at risk of cardiac arrest and kidney failure, writing: “Our patient could die at any moment.” The Russian state penitentiary service, FSIN, confirmed Monday that Navalny would be transferred to a hospital for convicts in the city of Vladimir. The FSIN statement said Navalny’s condition has been deemed “satisfactory” by prison doctors, and that he has agreed to take vitamin therapy. Navalny’s allies have have called for nationwide protests on Wednesday to show support for him—the same day that President Vladimir Putin is set to deliver his annual state of the nation address.