CANNES, France (Reuters) -Russian director Kirill Serebrennikov used his appearance at the Cannes Film Festival on Monday to launch a protest against the detention and trial of a playwright and a theatre director in Moscow.

Serebrennikov - who premiered his film "Limonov: The Ballad" at the movie extravaganza - held up a picture of Russian director Zhenya Berkovich and playwright Svetlana Petriychuk at a news conference in the French Riviera resort town.

"Today the trial started of these amazing young women," he said. "They didn't do anything wrong, they just staged a play that won a national theatre award. And for a year now they have been jailed."

Both have been held on charges of "justifying terrorism" through the play "Finist, the Brave Falcon" - written by Petriychuk and premiered in 2020 under Berkovich's direction - which is about Russian women who married Islamic State fighters.

The trial started on Monday, Russian media reported.

The women were added to Russia's official list of "terrorists and extremists" in April, joining thousands of people and entities who have been similarly designated in a crackdown on perceived subversive activity that intensified after Russia launched its invasion of Ukraine in 2022.

The Kremlin does not comment on individual cases but says Russia is engaged in an existential struggle with the West and needs to robustly uphold its laws and defend itself.

Serebrennikov's film, which stars Ben Whishaw in the title role, premiered at Cannes on Sunday.

It follows Limonov from the 1960s in his hometown of Kharkiv to Moscow, New York, Paris and finally to post-Soviet Russia, where he co-founded a left-wing and ultra-nationalist political party in the early 1990s.

"Limonov: The Ballad" - based on a book by French author Emmanuel Carrere - shows the main character's journey from poet to aspiring political leader, with a postscript saying he supported Russia's 2014 annexation of Crimea before his death in 2020.

The Cannes festival has banned official Russian delegations from attending since 2022, but Serebrennikov, who has spoken out against the invasion of Ukraine, also attended that year with his film "Tchaikovsky's Wife".

(Reporting by Tom Little, Miranda Murray and Lucy Papachristou, Editing by Andrew Heavens)

By Tom Little and Miranda Murray