WASHINGTON -- US National Security Advisor Mike Waltz has assumed "full responsibility" for a leaked group chat discussing an upcoming strike in Yemen.

"I take full responsibility. I built the group," Waltz said in an interview with Fox News Channel on Tuesday.

"It's embarrassing. We're going to get to the bottom of it," he said on the channel's "The Ingraham Angle."

Jeffrey Goldberg, editor-in-chief of The Atlantic, wrote on Monday that he was invited on March 11 to join a group chat named "Houthi PC Small Group" on Signal, a popular encrypted messaging app used by journalists and government officials.

Upon joining, he discovered that several high-ranking officials, including Waltz, Vice President JD Vance, Secretary of State Marco Rubio and Secretary of Defense Pete Hegseth, were discussing plans for a forthcoming strike on the Houthis in Yemen.

"According to the lengthy Hegseth text, the first detonations in Yemen would be felt two hours hence, at 1:45 p.m. eastern time," Goldberg recalled in his article. "So I waited in my car in a supermarket parking lot. If this Signal chat was real, I reasoned, Houthi targets would soon be bombed. At about 1:55, I checked X and searched Yemen. Explosions were then being heard across Sanaa, the capital city."

The incident is widely considered a major national security breach, prompting Democratic lawmakers to demand answers from the White House in multiple letters.

US President Donald Trump defended Waltz in front of reporters at the White House on Monday. "I don't think he should apologize," he said. "I think he's doing his best. It's equipment and technology that's not perfect."

According to Fox News, Trump has no plan to fire Waltz over the incident.

During an interview with NBC News on Tuesday, Trump said that a staffer from Waltz's office inadvertently included Goldberg in the group chat. He also claimed that this had "no impact at all" on the airstrikes in Yemen.