Russia has released a convicted opposition activist who says he was tortured in prison.

Ildar Dadin left his jail on Sunday in the remote Altai region in southern Siberia after Russia's Supreme Court annulled his two-and-a-half-year sentence last week.

Russia's Novaya Gazeta newspaper quoted him as saying: 'I will continue to fight with this false regime so that human rights will be observed, like in the civilised world.'

Dadin was convicted in December 2015 of breaking strict legislation regulating public demonstrations passed by Russia in 2014. Human rights groups described Dadin as a political prisoner who was only involved in non-violent protests.

Last year Dadin said he was tortured by prison guards who carried out beatings and threatened to rape him.

- See more at: Opposition activist released by Russia