CHICAGO (AP) _ The Art Institute of Chicago and its school drew up under pressure from City Councial a full-page advertisement Friday apologizing for a student painting of the late Mayor Harold Washington in lingerie.

''It contains an apology for the distress and concern that the painting caused to the community,'' Art Institute spokeswoman Eileen Harakal said of the advertisement, which will run in Sunday newspapers.

The prestigious museum and school have been under fire since Wednesday, when City Council approved a resolution threatening to cut off subsidies to the institute if it did not take down the painting and apologize publicly.

Later Wednesday, a group of black aldermen stormed into the school to remove the picture by David Nelson. Police subsequently impounded the painting.

Titled ''Mirth and Girth,'' the painting depicts Washington in a frilly white bra, panties and stockings, with a pencil in hand.

At a meeting of black ministers Friday, the Rev. Willie Barrow, executive director of the civil rights group Operation PUSH, described the painting as ''the latest in a series of escalating attacks and insults against the black community.''

Washington was black; the artist is white.

''We would like to see calm in the community,'' said Ms. Harakal. ''We never intended for there to be any unrest in the first place and want to put the entire incident behind us and move on.''

The amount received by the institute in city subsidies was not immediately known.

Meanwhile, the Art Institute received dozens of calls Friday from people supporting an artist's right to show his work, Ms. Harakal said.

The American Civil Liberties Union and students at the school have threatened to sue the police and aldermen for allegedly violating the artist's civil rights.

A group of 200 students approved a statement Thursday saying the Constitution guarantees the right to display the painting, whether or not its content is offensive.

The painting, which was defaced with a five-inch gash on Washington's left shoulder, was returned to Nelson by police Thursday after the ACLU intervened with the city corporation counsel, said Jay Miller, ACLU executive director.