According to the Reuters news agency, Microsoft said the Commission had given it until Feb. 15 to rebut a December decision to fine the firm 2 million euros ($2.45 million) a day. In late December, the Commission said that Microsoft had not provided adequate documentation on the inner workings of Windows, a necessary move to give competitors a level playing field in building Windows applications.

At the time, Microsoft said it would fight the fines, and countered that the Commission was making its demands a moving target. Wednesday was to be the deadline for answering the Commission's charge.

Meanwhile, in Washington D.C., the Justice Department said Microsoft is responding too slowly to requests for technical information made by a court-appointed committee established to oversee the antitrust settlement brokered in 2002. Under that settlement, Microsoft is required to license some Windows protocols to outside firms.

"Since approximately mid-November, Microsoft has fallen significantly behind in responding to technical documentation issues submitted by the Technical Committee," the Justice Department said in a filing to federal court on Monday.

The department also said Microsoft had provided inaccurate information that led to problems setting up a test lab in India, which was to have begun verifying the submitted Microsoft protocols. "This is particularly troubling given that, as described during the last Status Conference, Microsoft has on several occasions been unable to provide accurate information regarding the setup of the India labs," the DoJ said in the papers filed with U.S. District Judge Colleen Kollar-Kotelly.

"Microsoft needs to dramatically increase the resources devoted to responding to technical documentation issues in order to get its performance back on track," said the department.