Moscow(CNN) Jailed Kremlin critic Alexey Navalny has been moved from a penal colony to a regional hospital for prisoners east of Moscow as concerns grow over his health.
Russia's Federal Penitentiary Service (FSIN) said in a statement Monday that the opposition leader had been moved to the hospital, which specializes in "dynamic" observation of patients. The hospital is located on the "territory" of another penal colony, in the Vladimir region.
The statement said that Navalny was in "satisfactory" condition and is being examined by a doctor every day. With Navalny's consent, he has been prescribed "vitamin therapy," the penitentiary service added.
Navalny has been on hunger strike since March 31, demanding "proper medical care" and to be examined by an independent doctor -- something his team claims he has been unable to get in the penal colony in Pokrov.
Navalny's supporters say that his medical condition is rapidly deteriorating. His press secretary said over the weekend that Navalny was "dying" and his doctors said medical tests showed he was at growing risk of renal failure and heart problems. CNN is unable to independently verify the state of Navalny's health.
His supporters also criticized the choice of prison hospital that Navalny was moved to. Ivan Zhdanov, the director of Navalny's Anti-Corruption Foundation (FBK), told CNN that "it's a transfer to the same torture colony -- only this is where seriously ill patients are transferred."
"This should be understood as the fact that Navalny's condition has worsened. And it worsened so much that even the torturer admits it," Zhdanov added in a tweet.
The move comes as international concern around Navalny's health builds, with some countries condemning Russian authorities.
On Sunday, United States national security adviser Jake Sullivan said the Biden administration was weighing options to punish Russia if Navalny dies in state custody.
"We have communicated to the Russian government that what happens to Mr. Navalny in their custody is their responsibility and they will be held accountable by the international community," Sullivan told CNN. "In terms of the specific measures that we would take, we are looking at a variety of different costs that we would impose and I'm not going to telegraph that publicly at this point."
"But we have communicated that there will be consequences if Mr. Navalny dies."
The European Union has called on Russia to grant Navalny "immediate access" to a medical professional "he trusts."
"The European Union is deeply concerned about reports that the Russian opposition politician Alexei Navalny's health in the penal colony continues to deteriorate even further. We call on the Russian authorities to grant him immediate access to medical professionals he trusts," the EU's High Representative for Foreign Affairs Josep Borrell said in a statement Sunday.
And nearly a dozen Russian politicians have published an open letter to Russian President Vladimir Putin, saying that he was personally responsible for the Navalny's life.
On Monday, Navalny adviser and former deputy energy minister Vladimir Milov said he welcomed the "solidarity shown by the international community," but said that the reaction so far has been "fairly slow."
"We're facing a situation where Alexey could die by the minute," Milov told CNN, noting that Navalny's medical tests, which were made public last week, were "absolutely disastrous," and that doctors fear for his life.
"This sort of muted reaction isn't something we expected, we expected stronger action on the part of international leaders regarding that," Milov said.
Kremlin spokesman Dmitry Peskov told reporters on Monday that "frankly ... the overwhelming majority of those who signed this letter have no information at all about whom and what this is all about."
Asked how the Kremlin perceives warnings from US officials that Russia will face repercussions if Navalny dies, Peskov said: "We in no way perceive such statements, which are voiced by representatives of other states. The state of health of convicts on the territory of the Russian Federation cannot and should not be a topic of their interests."
The escalating situation has led Navalny's allies to announce rallies across Russia on April 21 in support of him.
Russia's Interior Ministry has warned people to "refrain from participating in unauthorized actions," citing coronavirus restrictions.
The ministry said in a Monday statement that law enforcement agencies will not allow citizens "to destabilize the situation and will take all necessary measures to maintain law and order in the regions of the country."
"Any aggressive actions of participants of unauthorized public events, and even attempts to provoke clashes with law enforcement officers, will be regarded as a threat to public safety and [be] immediately stopped," it said.
For months, opposition activists have been met with a harsh show of force, demonstrated most clearly on January 31, when over 5,000 people were detained during nationwide protests in 85 cities in support of Navalny.
Navalny was sent to prison after a Moscow court on February 2 replaced his suspended sentence with jail time due to violations of his probation.
He was arrested when he returned to Moscow from Germany where he had been recovering from poisoning with a nerve agent. Navalny blames the Russian security services for placing Novichok in his underpants and the US and European Union largely agree and have sanctioned Russian officials for their involvement.
Navalny was sent to penal colony No. 2 in Pokrov in mid-March.