MOSCOW — A polarizing historical film about Russia’s last czar is providing a window into a modern debate about the growing political role of religion and the extent of artistic freedom in Vladimir Putin’s Russia.

Religious extremists in Russia have carried out arson attacks and are threatening more in a bid to prevent the nationwide release of “Matilda,” a big-budget movie that tells the true story of a romance between the future Nicholas II and Matilda Kshesinskaya, a prima ballerina in St. Petersburg. Nicholas II, executed alongside his entire family by communist revolutionaries in 1918, was canonized by the Russian Orthodox Church after the collapse of the officially atheist Soviet Union as part of an ongoing revival of religious beliefs in Russia.

Some Russian Orthodox Christians say “Matilda,” which is funded by the Culture Ministry, is blasphemous because it depicts the “holy” czar in erotic scenes. Christian State-Holy Rus, a radical Orthodox movement, warned in January that “cinemas will burn” if the movie is screened. “Those who love God and the people so much that they are ready to go to prison, or even face death, will begin to act,” read letters sent to hundreds of cinemas.

These were no empty threats.

The first attack was on Aug. 31, when unknown assailants attempted to start a blaze at the film studio of Alexei Uchitel, the director of “Matilda,” in St. Petersburg. Two weeks later, an opponent of the movie drove a minibus packed with flammable materials into a cinema in Yekaterinburg, the city in central Russia where the royal family was slaughtered. The incident happened early in the morning, and no one was hurt. The driver, a 39-year-old man who had protested the screening of the movie, was arrested.

The latest arson attack occurred in Moscow on Sept. 11, ahead of the planned premiere of the movie in the Russian capital, when two cars were set on fire outside the law firm that represents Mr. Uchitel. The screening was canceled, but the movie was shown that day amid heavy security in Vladivostok, in Russia’s far east. The movie is due for nationwide release on Oct. 25.

“Our supporters have begun to act,” Alexander Kalinin, the 33-year-old leader of Christian State-Holy Rus, told The Washington Times. “People are angry about this movie and are ready to take drastic measures. If they spit at our church and humiliate our faith, we are forbidden to tolerate this by the law of God.”

Mr. Kalinin insisted, however, that he was not personally involved in the arson attacks, and the Kremlin’s best-known spokesman was sharply critical of the violent protests the film has inspired.

“This whole story is now taking on a pretty ugly shape,” Dmitry Peskov told reporters on a conference call last week, saying police should investigate such “extremist action” against the film, according to a Radio Free Europe/Radio Liberty account.

“Discussion is one thing, but extremist action is something completely different. It is unacceptable that film distributors should select their repertoire under pressure from extremists who are flouting their rights,” he said.

Mr. Uchitel said he did not intend to cause offense and has urged critics to watch the entire movie before drawing conclusions. He also says his requests for police protection have been ignored.

Rising protests

The movie has been criticized by Natalia Poklonskaya, an ultraconservative lawmaker with Mr. Putin’s ruling United Russia party. Mr. Putin has cultivated ties with Russian Orthodox leaders in a bid to cement his own power.

Ms. Poklonskaya says “Matilda” should be banned because it insults the feelings of religious believers, a criminal offense in Russia since 2013. Ms. Poklonskaya, who invited widespread mockery this year when she claimed that a statue of Nicholas II in Crimea was weeping, acknowledges, however, that she has not seen the movie.

Ramzan Kadyrov, the Kremlin-backed strongman lin Chechnya, a mainly Muslim republic in Russia’s south, also has called for the movie to be pulled. Dozens of cinemas across Russia have said they will not screen “Matilda,” citing security concerns.

Alexander Medinsky, Russia’s culture minister, lashed out this month against the movie’s opponents, accusing Ms. Poklonskaya of stirring up religious tensions. He also urged law enforcement officials to crack down on Christian State-Holy Rus.

The powerful Russian Orthodox Church, which has close ties with the Kremlin, previously called for calm over the movie. On Friday, however, Alexander Shchipkov, a spokesman for the church, said the Culture Ministry had made a mistake in allowing the movie to be produced. Mr. Shchipkov said the movie “dances on the graves” of the czar and his family. Archpriest Vsevolod Chaplin, a former spokesman for the church, accused Mr. Medinsky of supporting “blasphemers, liars and immoral freaks.”

Although Mr. Putin earlier said artists should not produce work that could upset believers, the Kremlin on Friday condemned the actions of what it called “extremists.” It also said Mr. Putin plans to watch the movie when it is released nationwide. Stanislav Govorukhin, a Kremlin-linked movie director who heads the Russian parliament’s committee on cultural issues, called Christian State-Holy Rus “a mini-Islamic State” and said its supporters represented “dark forces.”

Mr. Kalinin, the Christian State-Holy Rus leader, boasts that his movement, which he says has tens of thousands of supporters nationwide, has the secret backing of influential senior figures in the Russian Orthodox Church. The church says it has no links to the movement.

“It’s likely that high-up church figures are involved with Christian State-Holy Rus,” Alexander Verkhovsky, director of the Moscow-based Sova Center, which researches political and religious extremism, told The Washington Times. “This makes it a problem for law enforcement officials to investigate the movement because they do not know in advance what they are going to discover.”

The row over “Matilda” comes amid an ongoing clash over values between Russian liberal and conservative groups. Orthodox Christian activists have physically attacked a number of “offensive” exhibitions in recent years and have forced the closure of “blasphemous” theater productions, including a performance of “Jesus Christ Superstar” in Siberia.

It’s hard to know what regular Russians feel about the movie. In a recent opinion poll by the Moscow-based Public Opinion Fund pollster, only 31 percent of Russians said they had heard about the controversy. Of those who knew about it, 60 percent said they approved of the film’s release.

Some Russians said they would go see “Matilda” simply to support freedom of speech.

“I’ll go three times to the cinema and buy tickets for another three screenings just to show these religious fanatics that they can’t tell me what I can and can’t watch,” said Dmitry Krasnov, a computer programmer in Moscow.