Russian opposition leader Alexei Navalny died in the Kharp prison, in the Russian Arctic, this Friday. After the information became known, a video of Navalni sending a message to his followers in case of his death went viral on social networks.

It is the cut of an Oscar-winning HBO documentary by Canadian director Daniel Roher. The production tells how Navalny was poisoned by the Russian regime. "You're not allowed to give up. If they decide to kill me, it means that we are incredibly strong," was one of the phrases that social media users remembered the most.

Considered the most important critic of President Vladimir Putin in the last decade, Navalny was serving a 19-year prison sentence for various crimes, mostly for convictions based on political motivation.

At the end of last year he was transferred to an Arctic penal colony, considered one of the harshest prisons in Russia and located in the city of Kharp.