Atlantic editor-in-chief Jeffrey Goldberg joined ABC News Live to discuss the moment he realized he had been added to a Signal group chat with top government officials discussing a U.S. attack on Houthis in Yemen.

“My reaction was, I think I’ve discovered a massive security breach in the United States national security system,” Goldberg told Prime’s Linsey Davis on Monday.

This comes after the White House confirmed on Monday that the Signal group chat that inadvertently included Goldberg “appears to be authentic.”

“It’s almost automatically true that if the editor-in-chief of The Atlantic is being given access to this kind of information, weapon systems and packages and timing and weather in Yemen and all kinds of information about sequencing of particular events, then obviously there’s a security breach,” Goldberg told Davis.

Goldberg said he initially thought it might have been a “spoof” or “hoax,” but that “it became sort of overwhelmingly clear to me that this was a real group” once the attack occurred.

He said he removed himself from the chat and is “no longer privy to what, if anything, is going on in the chat.”

“I watched this Yemen operation go from beginning to apparent end, and that was enough for me to learn that there’s something wrong in the system here that would allow this information to come so dangerously close to the open, to the wild,” he said.

White House National Security Council spokesman Brian Hughes shared with ABC News the statement he provided to The Atlantic confirming the veracity of a Signal group chat, which Goldberg said appeared to include Defense Secretary Pete Hegseth, Vice President JD Vance, White House national security adviser Mike Waltz and Secretary of State Marco Rubio, among others.

“At this time, the message thread that was reported appears to be authentic, 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 our servicemembers or our national security,” Hughes said in the statement.

Hegseth denied how the story was characterized, saying, “nobody was texting war plans.”

“I’ve heard how it was characterized. Nobody was texting war plans, and that’s all I have to say about that,” Hegseth told reporters on Monday.

In the wake of the Signal chat’s surfacing, top Democrats have called for an investigation into the incident.

“The leak of sensitive national security information by the Trump administration on a non-classified system is completely outrageous and shocks the conscience,” House Minority Leader Hakeem Jeffries said in a statement.