Defense Secretary Lloyd Austin has been hospitalized since Jan. 1

US Secretary of Defence Lloyd Austin looks on during a joint press conference with Israels defence minister, in Tel Aviv on December 18, 2023. (Photo by Alberto PIZZOLI / AFP) (Photo by ALBERTO PIZZOLI/AFP via Getty Images)

Defense Secretary Lloyd Austin has been hospitalized since Monday due to complications following a minor elective medical procedure, his press secretary said, in the Defense Department’s first acknowledgement that Austin had been admitted five days earlier to Walter Reed National Military Medical Center.

Air Force Maj. Gen. Pat Ryder said Friday that it was not clear when Austin would be released from the hospital, but said the secretary was "recovering well" and resumed his full duties Friday evening from his hospital bed.

The Pentagon’s failure to disclose Austin’s hospitalization is counter to normal practice with the president and other senior U.S. officials and Cabinet members. The Pentagon Press Association, which represents media members who cover the Defense Department, sent a letter of protest to Ryder and Chris Meagher, the assistant defense secretary for public affairs.

"The fact that he has been at Walter Reed National Military Medical Center for four days and the Pentagon is only now alerting the public late on a Friday evening is an outrage," the PPA said in its letter. "At a time when there are growing threats to U.S. military service members in the Middle East and the U.S. is playing key national security roles in the wars in Israel and Ukraine, it is particularly critical for the American public to be informed about the health status and decision-making ability of its top defense leader."

The White House has refused to say when or how it had been notified of Austin’s hospitalization, and it referred questions to the Pentagon.

GettyImages-1245772381.jpg

FILE: From L to R, US Defense Secretary Lloyd Austin, Secretary of State Antony Blinken, Chairman of the Joint Chiefs of Staff Gen. Mark Milley and Attorney General Merrick Garland arrive to attend the joint press conference of US President Joe Biden

When Attorney General Merrick Garland went in for a routine medical procedure in 2022, his office informed the public a week in advance and outlined how long he was expected to be out and when he would return to work.

Ryder, the Pentagon spokesman, cited an "evolving situation," and said that due to privacy and medical issues, the Pentagon did not make Austin’s absence public. He declined to provide any other details about Austin’s medical procedure or health.

Austin, 70, spent 41 years in the military, retiring as a four-star Army general in 2016.

In a statement, Ryder said that at all times, Deputy Defense Secretary Kathleen Hicks "was prepared to act for and exercise the powers of the Secretary, if required."

RELATED: US forces shoot down ballistic missiles, kill Houthi gunmen in Red Sea

Austin's hospitalization comes as Iranian-backed militias have repeatedly launched drones, missiles and rockets at bases where U.S. troops are stationed in Iraq and Syria, leading the Biden administration to strike back on a number of occasions. Those strikes often involve sensitive, top-level discussions and decisions by Austin and other key military leaders.

The U.S. is also the chief organizer behind a new international maritime coalition using ships and other assets to patrol the southern Red Sea to deter persistent attacks on commercial vessels by Houthi militants in Yemen.

In addition, the administration, particularly Austin, has been at the forefront of the effort to supply weapons and training to Ukraine, and he's also been communicating frequently with the Israelis on their war against Hamas.