US State Department says the move is part of ongoing campaign to destabilise Ukraine amid Russian troop build-up.
Russian police detained several allies of Kremlin critic Alexey Navalny on Tuesday and raided two of his regional offices, a protest monitoring group said, a day before his supporters plan to stage mass protests over his treatment in jail.
Navalny, 44, declared a hunger strike at the end of March over what he said was the refusal of prison authorities to treat him properly for acute back and leg pain.
Following reports about his declining health since then, and recent warnings he “could die at any moment”, Russia’s prison service on Sunday said he had been transferred to a hospital for prisoners.
The service said Navalny’s condition had been deemed “satisfactory” but added that he had agreed to receive “vitamin therapy”.
However, his allies said he had still not received proper medical care, despite being moved.
Navalny’s doctors and lawyers on Tuesday arrived at the penal colony in Vladimir, a city 180km (112 miles) east of Moscow, where he is now being held and requested access to him.
But they were told the director of the facility was unavailable and were kept waiting for hours.
“He is very weak. It’s difficult for him to speak and to sit up,” Navalny’s lawyer Olga Mikhailova told reporters outside of the prison colony.
Mikhailova called for the opposition figure to be transferred to a civilian hospital in the capital, Moscow.
Another of Navalny’s lawyers, Vadim Kobzev, suggested he was currently being kept in a solitary ward at the hospital for prisoners, which reportedly specialises in tuberculosis treatment. Kobzev said on Twitter that the Kremlin critic had been given a glucose drip.
Navalny’s allies also reiterated their plan to take to the streets on Wednesday evening.
Pro-Navalny protests outlawed
Authorities have warned people not to take part in the planned demonstrations, which will coincide with Russian President Vladimir Putin’s annual state of the nation address.
The Kremlin has denounced the rallies as illegal, setting the stage for a confrontation between police and demonstrators and raising the possibility of another bout of extensive arrests.
Nationwide pro-Navalny protests earlier this year resulted in thousands of his supporters being detained.
In Moscow, the mayor’s office said a planned protest would not be authorised because of the coronavirus pandemic.
Authorities said the city centre of Yekaterinburg, in the Urals, will be closed to traffic from early evening because of a military parade rehearsal.
In an apparent bid to further dissuade protesters, police conducted raids at Navalny’s regional offices in the southern city of Krasnodar and the central region of Chelyabinsk, according to OVD-Info, a group which monitors protests and activist detentions.
Five pro-Navalny activists in different regions were detained on various charges, it said.
Navalny’s activist network is facing mounting pressure from Russian authorities.
On Friday, state prosecutors in Moscow said they wanted to label his regional groups and anti-corruption foundation as “extremist”, a move that would essentially outlaw their activity.
Human rights activists say the designation would paralyse their activities and expose their members and donors to prison sentences of up to 10 years.
US, EU try to pressure Moscow
Navalny’s case has also plunged relations between Moscow and the West to post-Cold War lows.
The European Union and United States have urged Russian authorities to grant Navalny immediate access to medical treatment, while US President Joe Biden’s White House said on Monday that Moscow would be held to account for his fate.
Those comments were echoed by top EU diplomat Josep Borrell, who said the bloc held Russian authorities “responsible” for Navalny’s “health situation”.
Both Washington and Brussels have also called for Navalny’s release from prison.
The Kremlin critic was arrested in January upon his return to Russia from Germany, where he spent five months recovering from a nerve-agent poisoning that he blames on Russian officials.
The Kremlin denies such allegations.
In February, he was sentenced to two and a half years in prison for violating the terms of his probation while convalescing in Germany. Navalny has rejected the case against him as fabricated.
Russia has dismissed the calls from abroad for his release as foreign interference in its domestic affairs.
Kremlin spokesman Dmitry Peskov on Tuesday said Navalny’s case was a matter for the state prison service or the prosecutor’s office.