An online censorship-monitoring group says Venezuela's state-run internet provider has been restricting access to YouTube and some Google services.
Europe-based NetBlocks says CANTV also briefly restricted access Tuesday to Twitter and Facebook after opposition leader Juan Guaido and freed colleague Leopoldo Lopez said they were rallying military units to oust President Nicolas Maduro.
NetBlocks director Alp Toker says Google's search engine was not affected, but Microsoft's Bing was.
NetBlocks says the blockages were not fully effective but marked a sudden escalation of censorship.
Google and Microsoft did not immediately respond to requests for comment.