Four Bronx schoolboys were forced by a school employee to strip down to their underwear and jump up and down, their parents allege in a federal lawsuit filed yesterday.

In the incident, which occurred during the last school year, the fourth graders were pulled from a gym class at P.S. 186X by Julio Passaro, who worked as a liaison between the special-education school and the parents, and taken to a private room on the second floor, the parents say.

One by one, the children, who had been wrongly accused of stealing a teacher’s ring, were forced to take off their shoes, socks, shirt, and pants, the parents say. The parents say that when the boys were undressed, wearing only their underwear, Mr. Passaro patted down each one, supposedly searching for the missing ring. Nothing was found.

Mr. Passaro then ordered each student to jump up and down, apparently to jostle out a hidden ring. Again, nothing was found.

“The strip searches of these children violated official Board of Education policy, violated State law, and violated the Constitution,” the lawsuit charges.

In a statement yesterday, the city Department of Education said the “accused family worker” has been reassigned to administrative duties pending an investigation of the allegations.

The lawyer representing the four boys, Ilann Maazel, said the incident occurred April 2 at the Walter J. Damrosch School on Jennings Street. After filing a lawsuit in U.S. District Court in Lower Manhattan, Mr. Maazel and the boys’ mothers talked publicly yesterday for the first time about what they called “reckless, willful, wanton, and malicious” abuse.

“To subject these 10- and 11-year-old children to strip searches was simply unconscionable,” Mr. Maazel said. “This should never happen in a New York City public school, or in any school. There is no question that these strip searches violated the law.”

Rules issued by Schools Chancellor Joel Klein make clear, “Under no circumstances shall a strip-search of a student be conducted.”

The episode apparently began when a teacher misplaced her ring. She asked the students in a morning woodshop class if they had stolen her ring. None of the students confessed.

Later that day, the four boys, identified only by their initials in the lawsuit, were allegedly removed from gym class by Mr. Passaro without what the complaint calls “probable cause, individual suspicion, or any reason whatsoever,” and were asked again if they had stolen the ring. All of them again denied it.

Mr. Passaro told the boys they would be taken “downtown” and sent to “jail” for a long time if they had stolen the jewelry, and then took them to the second floor of the school for their individual strip searches.

The education department’s statement said, “The allegation is being investigated by the Chancellor’s Office of Special Investigations. Further disciplinary action is pending the outcome of the investigation.”