NEW YORK (AP) - The Brooklyn Museum of Art has taken New York City to court over an upcoming exhibit of controversial British art, catapulting a philosophical debate into the legal realm.

Museum trustees asked for a federal court order Tuesday protecting the institution from retaliation by the city over a show that includes a dung-decorated portrait of the Virgin Mary.

``We are seeking a declaration from the court that no punishment may be inflicted by the city at all against the museum for the exercise of its First Amendment rights,'' said museum attorney Floyd Abrams.

Mayor Rudolph Giuliani has threatened to evict the museum from its city-owned home and to freeze at least $7 million in funding unless the museum backs down. Deputy Mayor Joseph Lhota said that a $500,000 check due to the museum on Friday would not be issued.

The exhibit is scheduled to open Saturday. It includes works that Giuliani has called ``sick'' and ``disgusting.''

``The Holy Virgin Mary'' the work at the center of the dispute, was among a collection of Chris Ofili's work that won Britain's prestigious Turner Prize for contemporary art.

Ofili, who is a Roman Catholic of Nigerian descent, remained in his London studio Tuesday and refused to comment. He told The New York Times that elephant dung is symbolic of the beauty of the natural surroundings he observed during a visit to Zimbabwe.

Glenn Scott Wright, Ofili's London representative, called the mayor's intervention ``totalitarian and fascist, a reprisal of the Nazi regime's censorship of the contemporary art of its time which it labeled `degenerate art.'''

The museum's board voted Tuesday to post signs warning of the explicit nature of some of the works rather than require visitors under 17 be accompanied by an adult. Giuliani had said that condition violated the museum's lease with the city, which calls for open admission.

The leaders of more than a dozen of the city's cultural institutions - including the Metropolitan Museum of Art, the Museum of Modern Art and the Solomon R. Guggenheim Museum - warned Giuliani in a letter that his actions set ``a dangerous precedent.''

Freezing the Brooklyn Museum's funds ``would have a chilling effect on all cultural institutions' ability to exercise their professional judgment and take the risks inherent in experimentation,'' the letter said.