A court in Moscow has issued an arrest warrant for the widow of Russian opposition leader Alexei Navalny on charges of extremism, according to state media.

The charges brought against Yulia Navalnaya, who lives outside Russia, in absentia are to do with her alleged “participation in an extremist society”, Tass news agency said.

Navalny was Russia’s most significant opposition leader of the past decade. He died in February in an Arctic Circle jail. Russian authorities said he died of natural causes - but his widow said Navalny had been “tortured, starved, cut off and killed” by Russia’s president Vladimir Putin.

Navalny had been serving 19 years on extremism charges that were widely seen as politically motivated.

Responding to the arrest warrant against her, Yulia Navalnaya posted on X: "When you write about this, please do not forget to write the main thing: Vladimir Putin is a murderer and a war criminal.