Microsoft Corp.'s top lawyer met Friday with federal and state officials for talks aimed at heading off government antitrust suits against the software company.

The Justice Department said its antitrust chief, Joel Klein, met face-to-face with Microsoft's chief lawyer, William Neukom, and with the attorneys general of Iowa and Connecticut. Negotiations were expected to go through the weekend."The significance of these talks is not to be underestimated," said Mitchell S. Pettit, director of ProComp, a coalition of software and related companies concerned about Microsoft's market power. "What is being discussed this weekend could shape this industry for the next two decades."

A lawyer from the office of Massachusetts Attorney General Scott Harshbarger was at the Justice Department Friday to monitor the negotiations. Massachusetts is one of as many as 19 states that have prepared an antitrust complaint against Microsoft, which could be filed as a parallel action to a lawsuit threatened by the Justice Department.

Lawsuits were due to be filed Thursday, but Microsoft offered new concessions that prompted a new round of talks.