State media and communications watchdog Roskomnadzor said a Wikipedia article titled "Smoking Cannabis" must be taken down because it includes information on the methods of extraction, production and consumption of narcotics, RIA Novosti reported Friday.
The notification from Roskomnadzor means the site's administrators must remove the banned content within 24 hours or be obliged to block access to Russian-language Wikipedia within Russia.
If the provider fails to comply the network operator will block access to the website, the Roskomnadzor notification said.
Internet censorship has become a bone of contention in Russia after passage of a law last year allowing extrajudicial blacklisting of web content deemed to promote suicide, pedophilia or drug use.
The Russian-language division of Wikipedia temporarily suspended its work last July in protest against the law.