Jeffrey Goldberg, editor-in-chief of The Atlantic, said he was added to a group chat that included U.S. vice president JD Vance, defense secretary Pete Hegseth, national security advisor Mike Waltz, and director of national intelligence Tulsi Gabbard.

Goldberg said he was added to the group, which was named “Houthi PC small group” and included one “active intelligence officer,” by Waltz on March 13. To his surprise, the members then went on to share details of Houthi targets, weapons packages, and timing of an upcoming attack.

The report has raised questions about the Trump administration’s use of Signal, which has previously been classified by the Defense Department as an “unmanaged” messaging app and is not approved for official use.

In a 2023 memo, the Defense Department defined unmanaged apps, which also included platforms like WhatsApp and Apple iMessage, as those “NOT authorized to access, transmit, or process non-public DoD information.”

Instead, the U.S. government requires officials to use approved classified communication systems, such as a Sensitive Compartmented Information Facility (SCIF), to discuss secret data.

In his report, Goldberg also said that some of the messages in the group chat utilized Signal’s “disappearing messages” function, with some set to delete after one week and others after four weeks.

This has prompted concerns about potential violations of public records law by the U.S. officials.

One former government security leader, who asked for anonymity to discuss sensitive matters, told Fortune that all of the officials involved in the Signal group would have been required to preserve their communications under record laws.

The person added that none of the officials involved in the group chat had the authority to decide which of their communications did and didn’t apply to public record laws.

Jason R. Baron, a professor at the University of Maryland and the former director of litigation at the National Archives and Records Administration, told The Atlantic: “Under the records laws applicable to the White House and federal agencies, all government employees are prohibited from using electronic-messaging applications such as Signal for official business unless those messages are promptly forwarded or copied to an official government account.”

The officials’ use of Signal has been criticized by other former officials, including former national security adviser under President Trump’s first administration, John Bolton. 

“I couldn’t imagine anybody would use Signal,” Bolton told CNN. “I’ll just say this: If you think Signal is equivalent to U.S. government secure telecommunications, think again.”

How secure is Signal?

Signal is an encrypted messaging app popular with journalists, activists, whistleblowers, tech workers, and anyone else who wants to securely communicate information. Recently, it has also become increasingly popular with federal workers.

Many government workers have taken to the encrypted messaging app to discuss concerns over their job security as Elon Musk’s DOGE team attempts to slash government headcount with rounds of mass layoffs.

The former government security worker told Fortune that the use of Signal had become increasingly commonplace with government workers during the new Trump administration.

It’s seen as more secure because it is end-to-end encrypted and open-source, which allows security experts to audit it for vulnerabilities.

Unlike other messaging apps, Signal doesn’t store data like message logs, contacts, or locations on its servers. Users can also set some of the messages to disappear after certain lengths of time.

While Signal is allowed for personal conversations between government workers, is not approved for official government use. There are concerns that the app could be vulnerable to state-sponsored hackers or other security risks.

For example, a recent report from Mandiant—a cybersecurity firm owned by Google—uncovered an operation by Russian-linked spies who attempted to compromise the Signal accounts of Ukrainian military personnel by masquerading as familiar contacts.

Backlash from Democrats

The report has sparked an outcry from Democrats, who have widely condemned the officials for using an unauthorized platform for official communications. Waltz is also facing growing pressure to step down.

Democratic leader Chuck Schumer called it “one of the most stunning breaches of military intelligence I have read about in a very, very long time,” while former Transportation Secretary Pete Buttigieg said: “From an operational security perspective, this is the highest level of f‑‑‑up imaginable.”

Senator Chris Coons, a Democrat from Delaware, called the group chat a “shocking breach” in a post on X.

“If senior advisors to President Trump in fact used non-secure, non-government systems to discuss and convey detailed war plans, it’s a shocking breach of the standards for sharing classified information that could have put American service members at risk. There needs to be an oversight hearing and accountability for these actions,” he wrote.

Representatives for the Defense Department did not comment, while the Trump Administration did not immediately respond to a request for comment from Fortune. However, Brian Hughes, the spokesman for the National Security Council confirmed the authenticity of the Signal group to The Atlantic.

“This appears to be an authentic message chain, and we are reviewing how an inadvertent number was added to the chain,” Hughes told the outlet. “The thread is a demonstration of the deep and thoughtful policy coordination between senior officials. The ongoing success of the Houthi operation demonstrates that there were no threats to troops or national security.”

Donald Trump has also come to Waltz’s defense, calling it his “only glitch in two months, and it turned out not to be a serious one.”

The U.S. president told NBC News on Tuesday: “Michael Waltz has learned a lesson, and he’s a good man.”

Waltz has lashed out at The Atlantic over the report and denied that he messaged highly sensitive “war plans” to Goldberg.

“You’re talking about a deceitful and highly discredited so-called ‘journalist’ who’s made a profession of peddling hoaxes time and time again,” he said after landing in Hawaii Monday.