A Siberian independence rally appears to have been blocked in Russia's third-largest city, Novosibirsk.
Journalists and Twitter users in the city say as few as 40 people turned out for the march, which had been banned by city authorities for calling for a federalized Siberian Republic with greater autonomy from Moscow.
A beefed-up police presence was reported at the site.
Police in a second Siberian city, Omsk, reportedly closed off a central square to prevent protesters from gathering there.
Rally organizers say the federalization proposal, which would bring three-fourths of Russia's land mass under greater Siberian control, is no different than the plan backed by Russian President Vladimir Putin in eastern Ukraine.
Several Siberian activists were arrested in the run-up to the scheduled march, including organizer Konstantin Yeremenko.
Activists say they have been subject to intimidation and threats in the days leading up to the march.