Russia on Wednesday sentenced a blogger in the city of Tomsk to five years in a Siberian prison for "inciting extremism and hatred" after he criticized Russian military intervention in Ukraine in videos he posted to YouTube and Vkontakte, Russia's version of Facebook.

The unusually harsh decision against Vadim Tyumentsev, which also bans him from publishing any content online for three years after his sentence ends, is the latest evidence that the Russian government appears set to intensify its crackdown on dissenters online and that it is willing to dole out real prison terms to keep them quiet.

The crackdown began after Putin, who famously called the Internet a "CIA project," returned as president in 2012 and Russia passed a slew of laws that tightened the government's control over the flow of news and information online.

The Kremlin has gone so far as to say it is considering the creation of a "kill switch" to unplug the country from the Internet "in case of an emergency."

Kevin Rothrock, a Russian policy analyst and editor-in-chief of RuNet Echo, which covers all things related to the Russian Internet, told Mashable that Russia's restrictive measures are "still accumulating and the enforcers will have to keep looking busy, so 2016 promises to be worse, at least superficially," for the country's users.

A Russian teenager reads a message on Vkontakte, Russia's version of Facebook, at an Internet cafe in Moscow.

But things could be especially bad for the small core of politically-active Internet users, who face censorship, intimidation and even imprisonment for speaking out against Russia's leaders and the government's policies.

Radio Liberty's Russian service said the criminal case against Tyumentsev was launched in February, when prosecutors found fault with videos he had posted that included diatribes about Russia's role in the Ukraine crisis and corruption among local authorities.

Russia's Memorial human rights group called the jail sentence "outrageous" and called for the verdict to be overturned. Tyumentsev, who appeared stoic while standing in a courtroom cage taking notes as he listened to the verdict, said he would appeal.

Tyumentsev's case wasn't the first, and Russia analysts and human rights organizations fear it's unlikely to be the last.

Mark Lagon, president of the U.S.-based non-governmental organization Freedom House said in a statement after the sentencing that the Russian government is "determined to prevent free expression in any form, including in social media."

Russian courts in at least two other cases have sentenced online activists to lengthy prison terms.

A court earlier this month handed down a two-year sentence to Darya Polyudova, an activist in Krasnodar, for online posts critical of Russia's policy toward Ukraine. She had also carried out one-person protests during which she chanted: "Not war with Ukraine, but revolution in Russia!"

Earlier this year, Rafis Kashapov, an activist from Tatarstan was sentenced to three years imprisonment after being convicted of extremism for allegedly calling for separatism and inciting ethnic hatred. The irony in the charges, of course, is that Russia has supported separatism in Ukraine. Kashapov's criticisms included railing against Russia's illegal annexation of Ukraine's Crimean peninsula.

Darya Polyudova holds a sign that reads "No war in Ukraine."

Online criticism of Russia's maneuvers in Ukraine specifically is something that authorities are working hard to quash, Andrei Soldatov, author of The Red Web: The Struggle Between Russia's Digital Dictators and the New Online Revolutionaries and an expert on Russian security services, told Mashable/

"The climate online changed significantly in February-March of 2014, when Putin delivered his Crimea speech [about] the 'fifth column' and national traitors," he said.

Alexander Zharov, head of Russia's Internet watchdog Roskomnadzor, which plays a major role in censoring content online and has banned hundreds of websites, including Reddit briefly this year, gave an interview with the news website Gazeta.ru on Tuesday. He told Russian Internet users they have nothing to fear, as long as they follow the rules for posting online.

"Listen, guys. I think that if you don't propagate extremism, don't swear, don't write about how great drugs are or how beautiful suicide is, and don't stick child pornography in your stories, then Roskomnadzor won't punish you for anything more," said Zharov.