Russia's internet monitoring agency has blocked 13 web pages linked to the Ukraine protest movement which helped oust the country's Russia-leaning president last week.
Roskomnadzor said in a statement published online that it had been ordered by the general prosecutor's office to shut down the pages on Russia's leading social media website, VKontakte.
The agency said the groups "propagandised the activity of Ukrainian nationalist groups", and accused them of encouraging "terrorist activity" and "participation in unsanctioned mass actions".
The largest pro-demonstration group, which has more than 500,000 members, was not accessible to users on Russian territory today.
While much of Russian media is state-controlled, the internet has so far remained largely free from censorship and has provided an active forum for anti-government criticism.
PA and AP