The decision by the judge, James E. Boasberg, came in response to a lawsuit filed this week by a nonprofit watchdog group American Oversight, which has accused President Trump’s national security team of violating federal records laws by using Signal — an encrypted commercial platform — to chat about the highly sensitive attack on Houthi rebels in Yemen.

The order by Judge Boasberg, who sits in Federal District Court in Washington, applied to top administration officials, including Mr. Trump’s national security adviser, Michael Waltz; Defense Secretary Pete Hegseth; Tulsi Gabbard, the director of national intelligence; Secretary of State Marco Rubio; and Vice President JD Vance.

It covered the period between March 11 and March 15 as the administration was putting together its plans to attack the Houthis.

The judge’s order was an early sign that at least some of the usual channels of accountability are still operating after the most senior administration officials engaged in an extraordinary breach of operational security and Mr. Trump’s attorney general, Pam Bondi, signaled that the Justice Department is not likely to investigate the matter.

Ms. Bondi, appearing on “The Ingraham Angle” on Fox News on Thursday night, included Judge Boasberg in the administration’s continuing attacks on federal judges who have recently pushed back against Mr. Trump’s repeated attempts to expand his own powers through executive actions.

Ms. Bondi said that Judge Boasberg needed to be removed from the Signal case and other Trump administration matters, along with other jurists.

At a hearing in Federal District Court in Washington on Thursday, Judge Boasberg made clear that he had issued his preservation order to be sure that none of the Signal messages were lost, not because he had made a finding that administration officials had done anything wrong.

American Oversight, which often seeks to pry loose information from the government under the Freedom of Information Act, has claimed that the administration’s use of Signal to discuss the attack plans violated the Federal Records Act, which requires official communications by agency officials to be preserved.

The revelation that top Trump administration officials not only discussed a pending military strike against Yemen on Signal, but also inadvertently invited a journalist, Jeffrey Goldberg, the editor in chief of The Atlantic, into the chat, has shocked the national security establishment. The lawsuit filed by American Oversight was in some sense a pre-emptive measure to ensure that the full record of what was said on the group chat was not deleted.

The Justice Department, in a filing on Thursday afternoon, said that one of the participants in the chat, Scott Bessent, the Treasury secretary, had already turned over the version of the messages that was on his phone.

In the same filing, a lawyer at the Pentagon asserted that he had requested a full copy of the chat from Mr. Hegseth, but it remained unclear whether it had been turned over.

Judge Boasberg began the court hearing where he ordered the chat to be preserved with an extraordinary, if muted, acknowledgment of the extreme pressure he is facing from Mr. Trump and his allies.

Early Thursday morning, Mr. Trump posted a message on social media falsely declaring that it was statistically impossible for Judge Boasberg to have been assigned not only the Signal chat case, but also other significant matters involving Mr. Trump. Those include a lawsuit challenging his use of an rarely invoked wartime statute to deport scores of Venezuelan immigrants from the country without a hearing or any other form of due process.

As Thursday’s hearing began, Judge Boasberg took a moment to explain to the public how he had come to be involved in the case in the first place. He said that he had been assigned to the Signal case by the normal process of random selection out of a total of 24 judges in the district — a clear rebuff of Mr. Trump’s false accusations against him.

The president and his allies have called for Judge Boasberg to be impeached for the decisions he has made in the immigration case.

In that matter, he has temporarily barred the administration from using a powerful and rarely invoked wartime statute to deport scores of Venezuelan immigrants from the country without the normal due process of a hearing.