A secret surveillance court that has been criticized for approving the vast majority of the government’s applications to spy on suspected terrorists and other targets reported Tuesday that the government had revamped roughly one-fourth of its requests in the face of court questions and demands.

The chief judge of the Foreign Intelligence Surveillance Court, Reggie Walton, told members of Congress in a letter that the court’s internal records show that more than 24 percent of government requests for recent warrants had “substantive” modifications in the wake of court review.

The disclosure of the new figure is intended to rebut critics who assert that the court provides a rubber stamp when the Justice Department seeks authority to monitor, track and eavesdrop on potential terrorists. The court faced new scrutiny following revelations this summer that the National Security Agency was secretly keeping the records of millions of Americans’ telephone calls, among other communications data.

The court, often called the FISA court after the 1979 law that created it, has typically approved more than 99 percent of government warrant requests. It has turned down no government warrants in the last four years — and denied just 10 applications of the 34,000 submitted in its history.

Walton decided this summer that the court would begin keeping its own tally of how Justice Department warrant applications for electronic surveillance fared — and would track for the first time when the government withdrew or resubmitted those applications with changes.

“During the three month period from July 1, 2013 through September 30, 2013, we have observed that 24.4% of matters submitted ultimately involved substantive changes to the information provided by the government or to the authorities granted as a result of Court inquiry or action,” Walton wrote in his letter to Sens. Patrick J. Leahy (Vt.) and Charles E. Grassley (Iowa), the chairman and ranking Republican, respectively, of the Senate Judiciary Committee. The letter was dated Friday but posted to the court’s Web site Tuesday.

Walton wrote that he believed the sample period was illustrative of the way the court generally works and that the court has always believed the 99 percent approval statistic failed to capture its back-and-forth with the government over its requests.

The court, which operates in secret and whose opinions are typically shielded from public view, faced criticism after The Washington Post and the Guardian reported that it had secretly approved a far-reaching effort to collect Americans’ phone records.

NSA programs are not subject to the typical court review, but U.S. officials have argued that the programs are legal and still subject to rigorous judicial oversight.

In recent weeks, a series of declassified opinions from members of the FISA court have revealed the court as a tough taskmaster when it believed the government ran afoul of court rules.

In a recently released opinion from 2009, Walton scolded the government for repeated violations of court orders and falsely assuring the court it was following required steps to protect Americans’ privacy.

Privacy procedures “have been so frequently and systemically violated that it can fairly be said that this critical element of the overall [phone records] regime has never fully functioned effectively,” Walton wrote. He added that the explanation of the misunderstanding of the court’s order by Gen. Keith Alexander, the NSA’s director, “strains credulity.”