The treatment of Navalny is seen in the West as politically motivated, as the Kremlin's popularity could threaten President Vladimir Putin's regime.
In March, Navalny was sentenced to nine years in prison and sentenced to nine years in prison for embezzlement and contempt of court.
Navalny appealed, but on Tuesday a local court in Moscow rejected the request.
The court announces that the prisoner will thus be transferred to a high-security prison.
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He has been described as the man Putin fears the most.
But who is Alexei Navalny?
Photo: TT