DES MOINES, Iowa - The plaintiffs in Iowa's class-action antitrust lawsuit against Microsoft Corp. claim they have uncovered information that indicates the software company is violating its 2002 agreement with the U.S. Department of Justice.

The alleged misconduct surrounds Microsoft's duty to share software hooks known as application programming interfaces, or APIs, which let disparate programs work together. The Iowa plaintiffs' attorneys have alleged that Microsoft has not disclosed certain APIs to other software developers who want to make programs compatible with Microsoft software.

Plaintiffs' attorney Roxanne Conlin asked the judge in the Iowa case, Scott Rosenberg, for permission to tell the Justice Department and the Iowa attorney general what her side knows. Rosenberg responded that she could provide the information if a court order or a subpoena were issued for it.

The API issue also has landed Microsoft in trouble with the European Commission, which imposed a 3-million-euro-a-day fine in July for failure to provide proper software documentation. In response, the company provided 8,500 pages of documentation in November.

Microsoft attorney Rich Wallis said he doubted the Iowa case had turned up any information that would surprise the federal government and its independent experts who monitor the 2002 antitrust settlement.

Microsoft must appear before a federal judge quarterly on the matter, and at the most recent hearing, in December, the judge said Microsoft was complying.

"All our work in this area has been exhaustively reviewed," he said.

The Justice Department declined to comment. Bob Brammer, a spokesman for the Iowa attorney general, said Iowa and other states involved in earlier Microsoft litigation also have a team that has been tracking Microsoft's compliance with court orders and would be interested in any information Conlin may have.