Deputy Secretary of Defense Kathleen Hicks was NOT told that Lloyd Austin was in the hospital's intensive care unit (despite assuming his duties as head of the Pentagon)

Defense Secretary Lloyd Austin's mysterious hospitalization was a secret hidden even from his deputy Kathleen Hicks, it has been revealed.

Austin, 70, is in the spotlight after failing to tell the White House about the planned surgery that left him in intensive care on New Year's Day due to complications.

It has now emerged that he did not tell his second-in-command, Hicks, until Thursday, even though she took on some of his responsibilities two days earlier.

Austin is just below Biden at the top of the command structure in the US military, and his duties require him to be available at a moment's notice.

Hicks was on vacation in Puerto Rico when Austin had surgery, but she wasn't told about it until days later, after she was asked to work over the holidays.

Austin, 70, is just under President Joe Biden at the top of the US military's command structure and his duties require him to be available at a moment's notice to respond to any kind of national security crisis

US Defense Secretary Lloyd Austin (pictured) is likely to keep his job despite apparently not informing the president that he is undergoing surgery and will be away for five days, according to former officials

Pentagon Press Secretary Major General Pat Ryder said CNN it was “not unusual” for the secretary to delegate certain responsibilities, but added that she was not aware of why she intervened on this occasion.

A department spokesperson told DailyMail.com that Austin “resumed full duties” from Walter Reed National Military Medical Center on Friday evening.

He was still in hospital but “recovering well” Sunday morning, the spokesman added.

They declined to reveal details of the surgery, citing “medical and personal privacy concerns.”

Despite a barrage of criticism of Austin from members of Congress over his mysterious disappearance, White House aides have told Politics that his job is not in jeopardy.

Several also highlighted Biden's deep personal bond with Austin, thanks to the former four-star general's close friendship with the president's late son, Beau Biden.

The officials, who spoke to Politico on condition of anonymity, said a senior Pentagon official is likely to lose his job because of the chaos.

“Someone needs to roll their heads,” said a former defense official.

“Someone decided not to make it public,” another ex-official agreed. That person will probably be gone soon.”

“Not telling the White House, Congress or the media that he is sick, and then telling the Pentagon staff that he is working from home is the next level. This is a problem.'

Some officials also noted that Alabama-born Austin was close to Beau Biden after they served together in Iraq and attended Catholic services side by side.

Lower-level assistants, including Sasha Baker and his deputy Kathleen Hicks, have replaced Austin in the interim. Hicks was reportedly on vacation in Puerto Rico but had to attend to some duties.

Despite a barrage of criticism from members of Congress and the media over Austin's mysterious disappearance, White House aides have told Politico that his job is not in jeopardy.

A department spokesperson told DailyMail.com that Austin “resumed full duties” from Walter Reed National Military Medical Center (pictured) on Friday evening.

Five days after the top national security official disappeared from the radar, Pentagon press secretary Major General Pat Ryder (pictured) offered a limited explanation of his absence

Five days after the top national security official disappeared from the radar, Pentagon press secretary Major General Pat Ryder offered a limited explanation for his absence.

“On the evening of January 1, Secretary of Defense Lloyd J. Austin III was admitted to Walter Reed National Military Medical Center due to complications following a recent elective medical procedure,” Ryder said.

“He is recovering well and expects to resume full duties today. The Deputy Minister of Defense was at all times prepared, if necessary, to act on behalf of the Minister and to exercise the powers of the Minister.”

Just a day earlier, Ryder gave a televised news briefing that conveyed a sense of business as usual at the Pentagon, offering Austin's condolences to ally Japan after the New Year's Day earthquake, for example.

But the past week has been anything but normal for the Pentagon, with US forces in the Middle East grappling with the regional fallout from the unfolding war between Israel and Hamas and launching a US retaliatory strike in Baghdad on Thursday.

The Defense Department's handling of Austin's hospitalization contrasts with the State Department's handling of then-Secretary of State Colin Powell's prostate surgery on December 15, 2003.

The then-State Department spokesperson issued a statement in the morning disclosing that Powell, a retired four-star general and former chairman of the Joint Chiefs of Staff, underwent surgery at Walter Reed Army Medical Center and remained there for several days would stay. before returning home.

Ex-DOD officials have said someone will likely be fired over the unrest — though Austin may be saved thanks to his personal connection to Joe Biden. (Image: Biden speaking at a White House meeting in January 2023, flanked by Austin and Antony Blinken)

Some officials who spoke to Politico on condition of anonymity said a senior Pentagon official is likely to lose his job because of the chaos. (Pictured: The Pentagon as seen on August 27, 2023)

It also said Powell would have a reduced schedule while he recovered from the surgery. Then-State Department spokesman Richard Boucher subsequently provided details of Powell's operation in his daily briefing.

Contacted by Reuters on Friday, Boucher said the main question regarding disclosure was whether Austin was under anesthesia or incapacitated.

“Was there a point in the process when he could not function as Secretary of Defense?” he asked. “If you're walking around and you have information and you have assistants in the next room and you can make split-second decisions… then there's probably no public need to make this public.

“The only necessity is to get you thrown out,” he added.