At least 10,000 women may have been improperly stripped and searched by Chicago police during the last five years, American Civil Liberties Union officials have charged.

The ACLU, which filed a class-action suit in U.S. District Court here Thursday seeking to stop the practice, said the nude body searches were routinely conducted on women in police stations who were there for even the most minor traffic violations.

In one case cited in the suit, a woman went to a police station to post bond for unpaid parking tickets so her impounded auto could be released. She allegedly was taken to an open cell, forced to strip, directed to squat, then bend over and "spread her cheeks."

The complaint said a male officer came into the cell before the search was completed. In some Chicago police stations, the ACLU protested, closed circuit television cameras made it possible for officers outside the search area to observe.

Lois Lipton, a staff attorney for the Illinois ACLU chapter which filed the suit, based the estimate of those victimized on the number of women police have had in custody in the last five years.

The suit seeks $125,000 for each of 50 "Jane Doe" plaintiffs and for every other woman improperly subjected to the searches. It also seeks to halt the strip searches "where the police have no reason to believe that the women are concealing anything," Lipton said.

Because of the intimate and personal nature of the complaint, the women sued under assumed names, but all are willing to testify under their own names if necessary.

Police Superintendent James O'Grady, who wasn't available for comment today, claimed earlier that such police searches were required by a State Correction Department rule that advises prison officials, "Strip searches should be conducted upon admittance." Corrections Director Gayle Franzen, saying the one-sentence guideline has been "seriously misinterpreted" by police, removed the directive from departmental rules.

Last Feb. 14, O'Grady announced new guidelines for strip searches. They prohibit cavity searching and require supervisors to authorize nude searches in writing.

However, Lipton said that "The criteria -- good judgment and discretion -- are the same, and they have already been proven to be not enough to stop this practice."

Since publicity of the searches in mid-February, women from Florida, Arizona, Minnesota and Wisconsin have called to complain about similar police searches in those states, she said. Meanwhile U.S. Attorney Thomas Sullivan and the Fbi/ are looking into alleged abuses of post-arrest strip searches conducted by police here.

In interviews, some of the women described the police searches as "almost like rape."

"What police are doing to women is crude and ugly," ACLU executive director Jay Miller has said. "All of the victims report that their searches were done under the most unsanitary conditions."

One woman was taken to detention because her car had a broken headlight and didn't have her license with her, the complaint said. A matron searched the woman's body without washing her hands, the complaint stated.

Another woman was brought to police headquarters after police stopped her for making an incomplete left turn. She didn't have her driver's license with her, but police confirmed she had a valid license before the search was conducted, the lawsuit said.

The complaint guotes the matron as saying, "If you don't cooperate, six guys will come in and do it for me."