"Navalny," a film that examines the poisoning of jailed Russian dissident Alexei Navalny, on Sunday won the Oscar for best documentary feature.

Canadian director Daniel Roher's movie looks at the political rise of Navalny, the most prominent opponent of Russian President Vladimir Putin, his poisoning with the nerve agent Novichok during a trip to Siberia in 2020 and the subsequent probe.

"There's one person who couldn't be with us here tonight -- Alexei Navalny, the leader of the Russian opposition, who remains in solitary confinement for what he calls -- I want to make sure we get his words exactly right -- Vladimir Putin's unjust war of aggression in Ukraine," Roher told the audience as he accepted the golden statuette.

The 46-year-old Navalny, who has been held for the past two years at a maximum-security prison outside Moscow after an embezzlement conviction, has accused Putin of being behind the poisoning attack.

"My husband is in prison just for telling the truth. My husband is in prison just for defending democracy," his wife Yulia Navalnaya said.

Kremlin spokesman Dmitry Peskov told reporters he had not seen the film but speculated there could be a "certain element of politicization of the subject" of the film.

"Hollywood also sometimes politicizes its work. Such things happen," Peskov said, referring to the award decision.

The film, which premiered at the Sundance film festival in January 2022, won a BAFTA last month.

It bested "All That Breathes," "All the Beauty and the Bloodshed," "Fire of Love" and "A House Made of Splinters."