Seven people were arrested Tuesday at a protest at the Moscow premiere of "Matilda", a controversial biopic of the last tsar that has drawn threats from religious extremists, police said.

Alexei Uchitel's film has outraged hardline Orthodox believers, who view tsar Nicholas II as a saint and object to the depiction of his affair with a ballerina.

The film's trailer triggered a wave of attacks in the country, including Molotov cocktails thrown at the filmmakers' offices in Saint Petersburg.

In Moscow, two cars were set alight outside the offices of Uchitel's lawyer last month.

Police said the arrests at the premiere were for disturbing public order. All of those held were Orthodox activists, some singing religious songs and one holding a banner describing the film as "slander", TASS news agency reported.

Around a dozen other demonstrators, some holding pictures of the tsar, were not arrested. "I am praying to God instead of insulting him. This film insults a holy family," one told AFP.

Earlier in the day Alexei Ryazantsev of the Karo Premiere distribution company said at screenings there would be "increased security measures, but so far just for the first weekend of release".

Distributors were still receiving messages about possible disruptions at screenings but they were being handled by police, he told reporters.

Uchitel said he had not expected such controversy and would not wish it on anyone.

"It's been very hard psychologically," he said. "As you know there have been threats... but the authorities have reacted and these people have been arrested".

In the Urals city of Yekaterinburg -- where the royal family was killed by firing squad -- a man drove a van filled with gas canisters into a movie theatre and set it on fire in apparent protest against the historical drama.

Last month, Russia's two biggest cinema chains Cinema Park and Formula Kino said they would drop the film from their lineup after threats, but later reversed their decision.

The attacks on the period drama have shaken Russia's liberal artistic community, which has long felt itself under pressure during President Vladimir Putin's conservative rule.

Putin has in recent years played up traditional values in a bid to win backing from everyday Russians and the powerful Orthodox Church.

But critics say the Kremlin's focus on Christian values has empowered religious hardliners and that they may not be able to control the outcome.

- Mixed response -

Nicholas II and his family were denounced in the Soviet period but are now viewed as holy martyrs by the Russian Orthodox Church.

The visually luscious, erotically charged "Matilda" focuses on the emperor's relationship with ballerina Mathilde Kschessinska before his marriage and ascent to the throne.

German actor Lars Eidinger -- who is known for playing in steamy art house films -- stars as the last tsar. Eidinger declined to travel to Russia for the film's premieres, citing security concerns.

Moscow ads describe "Matilda" as "the most anticipated film of the year" but the movie has received a mixed response, with journalist Marina Akhmedova writing: "Watching the fuss around the film has been much more interesting than watching the film itself".

Source: AFP