Representatives of the International Brotherhood of Teamsters secretly recorded a July meeting they had with their official court-appointed anti-corruption monitors, a federal judge said Tuesday.

The Teamsters used those recordings in an attempt last month to convince a court that the union shouldn't have to divulge internal communications to the monitors. The court rejected the union's argument, saying it must turn over the requested documents.

The extraordinary effort by the Teamsters reflects the increasingly bitter and high-stakes battle it has fought throughout the year against the Independent Investigations Office, the entity charged with enforcing a 1989 court consent decree with the federal government to rid the union of organized crime. The office is investigating alleged corruption by several top Teamsters officials. The union has repeatedly fought efforts to turn over internal emails and other documents relating to the inquiries, calling the requests excessive. It also accused the office of attempting to interfere in the union's leadership elections.

The Teamsters revealed the recording in a Nov. 18 filing with the District Court for the Southern District of New York. The union said that a lawyer representing it had recorded a July 20 meeting between its representatives and the investigation office's top official, Joseph diGenova, a former U.S. attorney for the District of Columbia, "in order to memorialize it accurately later via transcription." The union cited comments by diGenova at the meeting to argue that he had verbally given the union considerable leeway in terms of complying with the document requests.

The union's court filing doesn't indicate that, but diGenova and his staff apparently did not know they were being recorded. In a filing Tuesday, District Court Judge Loretta Preska said the union had "surreptitiously recorded" the July meeting. But the effort didn't work. Preska said the union had no choice but to fully comply with the Independent Investigations Office's request.

A spokesman for the Teamsters could not be reached. A representative of the Independent Investigations Office declined to comment.

The court documents were obtained by Teamsters for a Democratic Union, a dissident group within the union that opposes Hoffa's leadership.

The Independent Investigations Office has recommended that corruption charges be filed against four top Teamsters officials, including Secretary-Treasurer Ken Hall, the union's number two official. Charges also have been recommended against: William C. Smith, executive assistant to Teamsters President James. P. Hoffa; Vice President-at-Large Rome Aloise; and the union's former political director, Nicole Brener-Schmitz.

The Teamsters have charged that diGenova attempted to interfere with its November leadership elections by filing trumped-up charges against the union. Hoffa and Hall won re-election in the contest. Fred Zuckerman, who ran against Hoffa, has charged that the president used dirty tricks to retain his office. In early December, Zuckerman called for a re-run of the election.