MOSCOW (Reuters) - Attackers set fire to a building used by a Russian director whose film about the last czar s romance with a ballerina has been condemned by religious conservatives, Russian news agencies reported on Thursday. A Molotov cocktail was thrown in through a window, igniting a fire in a building in the city of St Petersburg that houses, among other organizations, the studio of director Alexei Uchitel, the news agencies reported. The fire caused minor damage to a part of the building occupied by a different film studio, Lendok. Uchitel s forthcoming film, called Matilda, is about a reputed love affair between Tsar Nicholas II, before his coronation, and ballerina Mathilde Kschessinska.  Some conservatives have called for the film to be banned, saying it besmirches the reputation of the late czar. The Russian Orthodox Church has designated him a saint. He and his family were executed soon after the 1917 Bolshevik Revolution.   I cannot think of any motivation (for the attack) other than it being a reaction to Alexei Uchitel making the film  Mathilda ,  TASS news agency quoted Lendok director Alexei Telnov as saying. The attack resulted in broken windows and a burned window sill in a part of Lendok s premises used for movie viewings, concerts and conferences.  It was a miracle there was not a big fire,  the agency quoted Telnov as saying. A spokesman for the St Petersburg police told Reuters officers were making checks after fire and smoke were spotted at the studio s address. An assistant to Telnov said he was busy making a film so could not comment. Uchitel s representatives could not be reached for comment. Uchitel s  movie is to be released in October. Natalia Poklonskaya, a member of the Russian parliament, has said she asked prosecutors to have the film s release stopped, saying it would  insult the religious feeling of believers.   