Republicans in Congress reacted with swift fury over reports that the Pentagon waited several days to inform top officials about the hospitalization of Defense Secretary Lloyd Austin.

Why it matters: Some GOP lawmakers are already calling for Austin to testify or even be ousted over what one described as a "serious breakdown" in communications.

Driving the news: Pentagon spokesperson Pat Ryder said in a statement on Friday evening that Austin was admitted to Walter Reed hospital on Jan. 1 "for complications following a recent elective medical procedure."

• Deputy Defense Secretary Kathleen Hicks, who was reportedly on vacation in Puerto Rico at the time, was "prepared to act for and exercise the powers of the Secretary, if required," Ryder said.
• Biden administration officials including national security adviser Jake Sullivan were not informed of the hospitalization until Jan. 4, according to Politico, which also reported that the Pentagon only notified Congress shortly before releasing the public statement on Friday.

What they're saying: "Very concerning. Sounds like the President didn't even know about it," Rep. Jim Banks (R-Ind.), a member of the House Armed Services Committee, told Axios. Politico reported that Biden likely learned of the hospitalization in a briefing from Sullivan.

• Banks added that Austin "has been a disaster since Day One and should be replaced by someone who will focus on making the military ready to fight and win wars instead of advancing woke political causes of the Biden admin. Enough is enough."
• "We are learning more every hour about the Department's shocking defiance of the law," Senate Armed Services Committee ranking member Roger Wicker (R-Miss.) said in a statement, arguing the incident "further erodes trust in the Biden Administration."
• Sen. Tom Cotton (R-Ark.), a member of the Armed Services Committee, said in a statement: "If this report is true, there must be consequences for this shocking breakdown."

The intrigue: Even some Republicans who are less reflexively hostile to the administration were critical of the incident.

• "It's not right the DoD leadership failed to notify the White House," said Rep. Don Bacon (R-Neb.), a moderate former Air Force general and Armed Services Committee member.
• "Nuclear command and control is priority number one, and the SECDEF is a key authority in this chain of command," he said. "The confusion here undermines deterrence."

The other side: Austin released a statement on Saturday saying he is "very glad to be on the mend and look forward to returning to the Pentagon soon."

• "I also understand the media concerns about transparency and I recognize I could have done a better job ensuring the public was appropriately informed. I commit to doing better," Austin continued, adding that he takes "full responsibility for my decisions about disclosure."

What we're watching: Several Senate Armed Services Committee members are pressing for the Pentagon, and Austin himself, to provide more information about the decision not to immediately disclose the hospital stay.

• Wicker said members of Congress "must be briefed on a full accounting of the facts immediately," and offered a list of questions he wants answered, including why the determination was made, who was involved and "to what extent was the Secretary incapacitated by his surgery?"
• Sen. Rick Scott (R-Fla.) said in a post on X that Austin "must come to [the committee] immediately, explain why this happened & who helped keep it from our nation's leaders."