Top congressional Democrats and former U.S. national security officials raised alarm bells on Monday over the Trump administration’s handling of highly classified information after Jeffrey Goldberg, editor in chief of the Atlantic, reported that Trump cabinet officials accidentally leaked active war plans to him in a group chat on a non-government-sanctioned messaging app.

Goldberg reported that U.S. National Security Advisor Mike Waltz added Goldberg to a group chat on Signal, a popular open-source encrypted messaging service, that appeared to include U.S. Vice President J.D. Vance, Defense Secretary Pete Hegseth, Director of National Intelligence Tulsi Gabbard, and other cabinet and senior national security officials.

The chat, which the White House has confirmed was authentic, pertained to plans for U.S. military strikes against the Iran-backed Houthi rebels in Yemen and discussed “operational details of forthcoming strikes on Yemen, including information about targets, weapons the U.S. would be deploying, and attack sequencing,” according to Goldberg.

The emerging scandal over the Signal group chat and apparent accidental leak could have legal implications and make allies wary of sharing intelligence with the United States—and Democrats wasted no time ripping into the Trump administration over Goldberg’s report.

“I am horrified by reports that our most senior national security officials, including the heads of multiple agencies, shared sensitive and almost certainly classified information via a commercial messaging application, including imminent war plans,” Democratic Rep. Jim Himes of Connecticut, the ranking member on the House Intelligence Committee, said in a statement.

“If true, these actions are a brazen violation of laws and regulations that exist to protect national security, including the safety of Americans serving in harm’s way,” Himes added.

Himes emphasized the “calamitous risks of transmitting classified information across unclassified systems” and said he intended to get answers from intelligence officials at a committee hearing scheduled for Wednesday.

Democratic Rep. Gregory Meeks of New York, the ranking member on the House Foreign Affairs Committee, in a statement called for an immediate hearing on “what might be the most astonishing breach of our national security in recent history, where top leadership from DOD, State, Treasury, the CIA and even the VP himself used a commercial messaging app—Signal—to communicate U.S. war plans, all the while unaware that a journalist was included in the group chat.”

Meeks said that Republicans have “regularly contrived security ‘scandals’ to attack their political opponents with years of nakedly partisan hearings and investigations,” adding that the Trump administration “proves yet again that hypocrisy and cynical politics aren’t the only defining characteristics of today’s GOP; rank incompetence is front and center.”

Democratic Sen. Elizabeth Warren of Massachusetts, who sits on the Senate Armed Services Committee, in a post on X decried the administration’s reported actions as “blatantly illegal and dangerous beyond belief.”

“Our national security is in the hands of complete amateurs,” Warren wrote. “What other highly sensitive national security conversations are happening over group chat? Any other random people accidentally added to those, too?”

Former intelligence officials also reacted with disbelief.

In a post on X, former Obama National Security Advisor Susan Rice said, “This is insane.”

“Can’t imagine conducting a Principals Committee meeting and discussing a highly classified op plan on Signal,” Rice added, using a term that typically refers to a group of cabinet-level national security officials.

Former Secretary of State Hillary Clinton, who was famously investigated and lambasted by Republicans for using a private email server while serving as the top U.S. diplomat under former U.S. President Barack Obama, also chimed in on the bombshell report. “You have got to be kidding me,” Clinton wrote on X.

Republican members of Congress have been slower to comment publicly on the story, though a few have.

Republican Sen. John Cornyn of Texas, who sits on the Senate Intelligence Committee, expressed concern. “Sounds like a huge screw-up,” Cornyn told reporters on the news, adding, “I can use a different word, but you get the drift.”

“I would hope the interagency would look at that. It sounds like somebody dropped the ball,” Cornyn said.

House Speaker Mike Johnson was less critical. “They’re going to track that down and make sure that doesn’t happen again,” he told reporters, before going on to tout the “success” of the recent U.S. strikes on the Houthis in Yemen.

The White House in a statement said that the group chat in Goldberg’s report “appears to be an authentic message chain, and we are reviewing how an inadvertent number was added to the chain.”

“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,” National Security Council spokesperson Brian Hughes added.

But U.S. President Donald Trump on Monday afternoon told reporters he had not heard about the Atlantic report. “I don’t know anything about it. I’m not a big fan of the Atlantic, to me it’s a magazine that’s going out of business,” Trump said. “You’re telling me about it for the first time.”