Alexei Navalny received a nine-year sentence in March for fraud and contempt of court.
Jailed Kremlin critic Alexei Navalny said on Tuesday he had been charged in a new criminal case and faced up to 15 years in prison if found guilty.
In a post on Instagram, Mr Navalny said he had been charged with creating an extremist organisation and inciting hate towards the authorities.
The charge comes on top of a nine-year sentence he received in March for fraud and contempt of court, before which he was already serving a 2-1/2 year sentence.
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