Jailed Kremlin critic Alexei Navalny said on Monday that a prison commission had designated him an extremist and a terrorist.
Navalny said on Instagram that he had been summoned before a commission which voted unanimously in favour of the change of status.
The designation marks a further escalation of official pressure against President Vladimir Putin's most prominent domestic critic, currently serving two-and-a-half years in prison for parole violations he says were trumped up to thwart his political ambitions.
Navalny made light of the announcement, saying that he welcomed the fact he was no longer designated a flight risk due to the change and so would be subjected to less frequent and stringent night time checks by guards.
"It's just that there is now a sign over my bunk that I am a terrorist," said Navalny in the post, which was published with the help of his lawyers.