MOSCOW--A plan to hold a bullfight in Russia's capital has erupted in disputes with Moscow's mayor threatening to ban the event and the organizers promising to sue him.

After pressure from bullfighting opponents, Mayor Yuri Luzhkov says he has decided to ban a Portuguese bullfight scheduled for Sept. 8-9, his spokesman said Monday.

The company sponsoring the event said it would sue the mayor's office if it interfered, according to media reports.

``Our activities have been thoroughly scrutinized by just about all possible state and city structures _ we are not violating any Russian law and, thus, banning the bullfight is illegal,'' Andrei Agapov, head of the Russian Academy of Entertainment _ the event's organizer _ told the English-language Moscow Times.

Animal-rights activists and members of a pro-Kremlin youth group, Walking Together, have held demonstrations against the bullfights. Billboards advertising the event have been vandalized, with the word ``cruelty'' scrawled across them.

Organizers of the bullfight say the event is not cruel to animals since the bull is not killed in the Portuguese version of the sport.

Even Patriarch Alexy II, the head of the Russian Orthodox Church, has joined the debate, saying the church opposes all forms of bullfighting.

``The public spilling of animal blood incites passion and provokes instincts of aggression,'' Metropolitan Kirill, chief of foreign relations for the church, told reporters this week. ``Bullfighting does not correspond to our national mentality.''