A former Army scientist suing the New York Times for libel has asked a federal judge to fine the newspaper $25,000 a day for refusing to disclose its confidential sources and to increase the fine amount by $25,000 each month in an attempt to encourage the paper to comply.

The scientist, Steven Hatfill, contends that a series of Times columns fingered him as responsible for the anthrax mailings in 2001 that terrorized the nation and killed at least five people. While the FBI searched Mr. Hatfill’s home and the Justice Department eventually named him as a “person of interest” in the anthrax case, neither the scientist nor anyone else was ever charged in connection with the crimes.

Last month, a federal magistrate in Alexandria, Va., where Mr. Hatfill’s suit was filed, ordered the Times to identify the sources for the five columns in dispute. A federal judge upheld the order, but the newspaper indicated the author of the columns, Nicholas Kristof, would persist in refusing to name his sources.

“There has been a certain ‘heads I win, tails you lose’ quality to the Times’s litigation of this issue so far,” an attorney for Mr. Hatfill, Thomas Connolly, wrote in a motion urging the fines. “In order to ensure that the officers, directors, and shareholders of the Times are fully involved in determining whether it wishes to ignore the judicial power of the United States, this court should impose a significant monetary sanction for each day of non-compliance.”

Mr. Connolly painted the Times’s refusal to comply as brazen and willful. “Courts, not newspapers, decide what evidence must be presented in court when the administration of justice so requires,” the lawyer wrote.

In a filing yesterday, counsel for the Times called the proposed fines “extreme, over-reaching and unwarranted.”

Attorneys for the Times insist that the newspaper is simply preserving its right to appeal the order to disclose its sources.

The Times also noted that 10 of the 12 sources Mr. Kristof relied on are known to Mr. Hatfill, either because they were not granted confidentiality or agreed to waive it. As a result, the names of only two sources are being withheld. Mr. Kristof has said both were FBI employees.

The Times’s lawyers also said Mr. Hatfill deliberately delayed giving his deposition in the case and that his attorneys’ bid to block further discovery by the Times is part of “a ruse designed to insulate plaintiff from giving any testimony under oath at all.”

A court hearing on the proposed sanctions is set for tomorrow.