A Russian news editor in Siberia was handed an eight-year prison sentence on Friday for publishing critical material on Moscow's Ukraine offensive, amid a sweeping crackdown on dissent within Russia.

Sergei Mikhailov, a journalist and editor in the Altai region, was arrested within weeks of the Kremlin’s 2022 military campaign, shortly after repressive laws banning criticism of Russia's actions in Ukraine were enacted.

He had published online posts about civilian deaths in the Kyiv suburb of Bucha and in Mariupol.

A court in Gorno-Altaisk sentenced the 48-year-old after finding him guilty of "knowingly spreading false information" about the Russian army.

Prosecutors said he was "motivated by political hatred."

Mikhailov ran the small online opposition social media channel "Listok" in Siberia's Altai Republic – a region that has sent many men to Ukraine.

In a court speech earlier this week, Mikhailov defended his reporting and harshly criticized the Kremlin for sending troops to Ukraine.

He said the Russian state narrative of labeling the Ukrainian leadership as "fascist" had "created a whole virtual universe in the information space, and this fog became stronger and stronger."

"My publications were aimed at countering this fog, so my readers would not be misled by lies, would not take part in armed conflicts, and would not become murderers or victims, thereby avoiding harm to the brotherly Ukrainian people," Mikhailov said in an audio of the speech published by Listok on social media.

More than 1,000 people have been prosecuted in Russia for criticizing the Russian offensive against Ukraine since the start of the conflict in February 2022, according to the monitoring group OVD-Info.