Despite the Signal scandal, National Security Adviser Mike Waltz will still travel to Greenland with the Vice President JD Vance and Second Lady Usha Vance, a White House official confirmed on an X post Thursday.

"He was always going," White House deputy press secretary Anna Kelly said in a post. "We’ve been confirming it for days."

The White House previously confirmed that Waltz was joining the trip with the second lady.

-ABC News' Michelle Stoddart

Senate Armed Services Committee Chairman Roger Wicker and Ranking Member Jack Reed sent a letter Thursday to the Department of Defnese Acting Inspector General formalizing the request for an inquiry into the Signal chat.

"This chat was alleged to have included classified information pertaining to sensitive military actions in Yemen. If true, this reporting raises questions as to the use of unclassified networks to discuss sensitive and classified information, as well as the sharing of such information with those who do not have proper clearance and need to know," they said.

Among the requests the senators asked for, were an assessment of Defense Department classification policies, and "assessment of whether any individuals transferred classified information, including operational details, from classified systems to unclassified systems, and if so, how."

-ABC News' Allison Pecorin

White House press secretary Karoline Leavitt was asked if the White House would hold anyone accountable for what happened and if it would potentially change its messaging on the incident.

“Well, we have never denied that this was a mistake, and the national security adviser took responsibility for that, and we have said we are making changes. We are looking into the matter to ensure it can never happen again," she said.

Asked if the White House would cooperate with any requests from Congress regarding the Signal chat, Leavitt left it open-ended.

“We haven't seen a request from Congress come through our inboxes yet, and when that does, we'll have an answer," she said.

-ABC News' Hannah Demissie

The Department of Health and Human Services confirmed on Thursday that about 10,000 full-time employees will soon lose their jobs, on top of the nearly 10,000 who have already left the agency in the last few months through buyout offers or early retirements.

That puts the total employees at around 62,000 people -- down from 82,000 at the start of the Trump administration.

"We aren't just reducing bureaucratic sprawl. We are realigning the organization with its core mission and our new priorities in reversing the chronic disease epidemic," HHS Secretary Robert F. Kennedy, Jr. said in a statement.

"This overhaul will be a win-win for taxpayers and for those that HHS serves. That's the entire American public, because our goal is to Make America Healthy Again," Kennedy said. Kennedy claimed the latest cuts would save taxpayers $1.8 billion per year.

Despite cutting nearly one-quarter of the agency, the department maintains that the restructuring won't impact "critical services."

The real-world impact of the newest round of cuts, however, remains to be seen. Already, cuts have hit top researchers at the National Institute of Health's Alzheimer's research center and disease detectives who identify new infectious diseases.

-ABC News' Cheyenne Haslett

Democratic Sen. Martin Heinrich and independent Sen. Angus King questioned intelligence officials on the content included in the Signal chat about a U.S. attack on Houthis in Yemen.

The Atlantic's Jeffrey Goldberg, the journalist who was inadvertently added to the message chain, told ABC News Live anchor Linsey Davis it contained sensitive information about weapon systems and timing, among other things.

Director of National Intelligence Tulsi Gabbard and CIA Director John Ratcliffe repeatedly said during Tuesday's hearing that the chat did not contain classified information.

"So the attack sequencing and timing and weapons and targets, you don't consider should have been classified?" King asked Gabbard.

"I defer to the secretary of defense and the National Security Council on that question," she responded.