Officers arrested more than 10,000 people during demonstrations that took place in January, in what was the largest show of defiance against Putin in years. Street demonstrations could symbolically start shortly after President Vladimir Putin is set to deliver his state of nation address on Wednesday.
In a message calling for the protests, his team said Navalny's life is now "hanging by a hair" and accused the Kremlin of "killing Navalny for a second time before the eyes of all Russian Federation".
Last week, Russian Foreign Ministry's spokeswoman, Maria Zakharova, said that the United States is making up "stories" about Navalny's detention conditions while the U.S. itself continues to violate the rights of prisoners.
"Of course, he will not be allowed to die in prison but I can say that Mr Navalny, he behaves like a hooligan", ambassador Andrei Kelin said.
On Saturday, Navalny's doctors said his health had rapidly deteriorated and demanded prison officials grant them immediate access.
Alexei Navalny's doctors say he could be close to death unless he gets medical treatment.
Meanwhile, on Sunday, Navalny's allies put out an urgent call for his supporters to take to the streets en masse across Russian Federation on Wednesday.
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She said they responded to an area that included a strip mall, several retail stores with a large apartment complex behind it. He said Broderick knew the victims but didn't elaborate on how or provide a motive for the shootings.
The European Union's top diplomats will discuss the situation on Monday, the EU's foreign policy chief Josep Borrell said in a statement, calling for the Kremlin critic to be granted "immediate access to medical professionals he trusts".
On Saturday, US President Joe Biden added his voice to a growing global chorus of protest at the treatment of the activist, describing his situation as "totally unfair".
Navalny's team said said next week's protests have become a final showdown with the Kremlin to stop Navalny's death and prevent the complete destruction of a democratic opposition in Russian Federation.
In an interview with the BBC, however, Russia's ambassador to Britain accused him of attention-seeking.
Navalny's lawyer said he missed the meetings because he was in Germany while he recovered from being poisoned with the Novichok nerve agent.
Navalny began refusing food on March 31 in protest at what he said was the refusal of prison authorities to provide him with adequate medical care for acute back and leg pain.
Russian Federation jailed Navalny for 2-1/2 years in February for parole violations he said were fabricated.
French Foreign Minister Jean-Yves Le Drian said Sunday that the European Union may impose new sanctions against Russia over the situation with Russian jailed opposition activist Alexey Navalny.