A Russian rights group says the number of criminal proceedings against bloggers in Russia more than doubled in 2013.
The Agora human rights association says 226 criminal cases against Internet users were registered last year, as compared with 103 such cases in 2012.
The report also describes an increase in physical attacks apparently targeting people over their blogging activity.
It also says administrative measures against bloggers, such as restricting a blogger's Internet access, more than doubled, to 514.
Human rights groups have criticized Russia for increasing restrictions on Internet content since President Vladimir Putin's reelection in 2012.
Experts say a law that went into effect on February 1 allows the blocking of websites that are seen as promoting "extremist" content, which could include calls for protests not approved by the authorities.
In one recent case, a court in the southern city of Rostov-on-Don in November sentenced a journalist to 18 months in jail for insulting a local judge in his blog.
The journalist, Sergei Reznik
, also survived what he claimed was an attack by unknown assailants who beat and shot him.
Opposition politician Aleksei Navalny has faced repeated prosecutions over a range of alleged wrongdoing since he came to prominence several years ago by using his blog to spotlight alleged corruption among Russian officials.
According to the Agora report, at least 30 criminal cases were opened last year against users of VK, or VKontakte, over what they published on Russia's largest social-networking website.
The report also says 37 civil lawsuits were filed in 2013 over the activities of bloggers.
It says bloggers were targeted with violence 48 times in St. Petersburg, while the number of attacks against bloggers also rose in Daghestan, the Altai Republic, and the Kostroma region.
The report notes the death of one blogger in 2013. In Moscow one year ago, a blogger was slain by her husband in an apparent domestic dispute.
In its latest report on online liberties, the U.S.-based group Freedom House says Russia was a partially free country in regards to the Internet, alongside countries including Azerbaijan, Kazakhstan, and Kyrgyzstan.
The report singled out Russia as an "important incubator of surveillance technologies and legal practices" concerning online activities, and said these practices are emulated by other former Soviet republics.
With reporting by Interfax, Gazeta.ru, and Deutsche Welle