Two of Canada's top arts groups are calling on Russia to release an incarcerated Ukrainian filmmaker who has been on a hunger strike for 34 days demanding the release of Ukrainian prisoners in Russia.

Luminato and the Toronto International Film Festival issued a joint statement Saturday in partnership with Belarus Free Theatre co-founder Natalia Kaliada calling for the release of Oleh Sentsov, as reported by 680 News.

Sentsov, a vocal opponent of Russia's annexation of his native Crimea, was convicted of conspiracy to commit terror attacks by a Russian military court in 2015 and sentenced to 20 years in prison.

Read alsoPoroshenko urges Macron to increase pressure on Russia for release of Ukrainian hostages

The case against him was largely seen as a retribution for his views, and Ukrainian authorities and art circles have mounted a worldwide campaign for his release.

Sentsov's lawyer Dmitry Dinze told the Meduza website last month that the filmmaker wrote a note to the prison's chief, vowing to stick to his hunger strike until Russia releases all of its Ukrainian political prisoners.

Sentsov's story is told in the Belarus Free Theatre's play "Burning Doors," which will be in Toronto next week as part of Luminato.

The play documents the experiences of three artists persecuted by their governments for their artistic expression and activism.

Luminato and TIFF say Sentsov and others they describe as political prisoners have been denied their basic human rights and their detention is a serious violation of international law.

"As the world's attention turns to Russia for the World Cup, we urge the international artistic community and Canadian government to join us in calling for the immediate release of Mr. Sentsov and 70 additional Ukrainian political prisoners," the statement said.

"We already knew that Oleh's situation was dire but after meeting with his sister Natasha, it's clear that the time for 'just words' has passed," Kaliada said. "What we need now are urgent and immediate actions to ensure that our colleague and fellow activist Oleh Sentsov is released."

On Thursday, the European Parliament urged Russia to release Sentsov, passing a resolution demanding Russian authorities free him "immediately and unconditionally, as well as all other illegally detained Ukrainian citizens in Russia and on the Crimean Peninsula."

Another action, led by PEN International, encourages the public to send appeals to Russian authorities, local ministries of foreign affairs and diplomatic representatives in Russia.

Margaret Atwood, Stephen Sondheim, Christiane Amanpour and Patrick Stewart are among dozens of artists and journalists who also have called for Sentsov to be freed in a letter released earlier this month through PEN America.