Donald Trump’s national security adviser, Michael Waltz, said on Tuesday he takes “full responsibility” for the group chat of senior administration officials that inadvertently included a journalist and leaked highly sensitive information about planned airstrikes in Yemen.

Waltz’s comments came one day after Jeffrey Goldberg, editor in chief of the Atlantic, revealed that he was added to a group on Signal, a private messaging app, that included vice-president JD Vance, defense secretary Pete Hegseth, secretary of state Marco Rubio and other high-profile figures discussing “operational details” of planned attacks on the Houthis in Yemen.

Goldberg’s account in the Atlantic suggested Waltz had mistakenly invited him to the chat. The prominent journalist remained in the group undetected as the president’s cabinet members discussed policy and coordinated a wave of bombings, an extraordinary breach that critics said put national security at risk.

When pressed by Fox News’s Laura Ingraham, Waltz accepted responsibility for making the Signal group, though he continued to deflect blame, insulted Goldberg and said he couldn’t explain how the mistake had occurred.

“It’s embarrassing, yes. We’re going to get to the bottom of it,” Waltz said, adding that he was consulting with Elon Musk: “We’ve got the best technical minds looking at how this happened.” When Ingraham asked “what staffer is responsible” for adding Goldberg to the Signal group, Waltz responded: “A staffer wasn’t responsible. I take full responsibility. I built the group. My job is to make sure everything is coordinated.”

When the Fox host asked how Goldberg’s number ended up in the group, Waltz responded: “Have you ever had somebody’s contact that shows their name and then you have somebody else’s number there? … Of course I didn’t see this loser in the group. It looked like someone else. Whether he did it deliberately or it happened in some other technical mean is something we’re trying to figure out.”

Waltz did not offer any evidence for how Goldberg could have “deliberately” ended up in the group.

Earlier in the interview, he said he didn’t know Goldberg or text with him, calling him the “bottom scum of journalists” while criticizing the media for focusing on the controversy.