The government will not seek to use any evidence it may have gleaned from wiretapping in its defense against a lawsuit filed by Muslim men over their detention in the period following September 11, 2001, a Department of Justice trial attorney said in a letter submitted to federal court in Brooklyn.

Lawyer Stephen Handler wrote in the letter filed Monday that he had not reviewed any conversations between the Muslim men and their attorneys. He also pledged that he would not seek to introduce as evidence any attorney client conversation that may have been intercepted.

Mr. Handler refused to say whether he is aware if any such spying occurred. The magistrate judge in the case, Steven Gold, had previously ordered Mr. Handler to disclose whether the trial team and any potential witnesses – who may include a former attorney general, John Ashcroft – were aware of intercepted attorney-client conversations. Although Mr. Handler said in court that he was not aware of any eavesdropping, he has since rescinded that answer. In Monday’s letter, Mr. Handler stated that any denial of knowledge of eavesdropping could “itself reveal classified information.”

The back and forth between the government and lawyers for the Center for Constitutional Rights, which represents the men, has occurred against the backdrop of a similar line of questioning in Washington. Last Friday, the Department of Justice indicated that attorney-client conversations were not “categorically excluded from interception” under the National Security Agency’s warrantless wiretap program, according to news reports of the Department of Justice’s written responses to dozens of questions from lawmakers.

At least one legal observer said there was no reason that any government eavesdropping would affect the present litigation in Brooklyn.

“When you talk about the NSA program, it is just assumed that the government is not going to be using it for any courtroom situation,” the former deputy assistant U.S. attorney general who established the Justice Department’s antiterrorism unit, Victoria Toensing, said. “It is being used for intelligence and matters of national security and protection.”

Ms. Toensing added that the Justice Department has traditionally made an effort to keep trial lawyers apart from its surveillance efforts, to prevent knowledge of eavesdropping from tainting courtroom efforts.

The Muslim men whose lawyers suspect to be under surveillance were detained for months after the terrorist attacks of September 11, 2001, before being deported. Some have accused their jailors of cruelty in the lawsuit filed in 2002. None of the men were accused of any terror-related charges. At least three of the men are currently in Toronto with their lawyers for further deposition, a spokesman for the Center for Constitutional Rights said, adding that the center would not comment on Mr. Handler’s letter until the judge has responded.