US defense secretary has been in hospital since Jan. 1

Defense Secretary Lloyd Austin has been hospitalized since Monday, due to complications following a minor elective medical procedure, Air Force Maj. Gen. Pat Ryder, the Pentagon press secretary, said. It was the department's first acknowledgement that Austin had been admitted — five days earlier — to Walter Reed National Military Medical Center.

Ryder said Friday that it's not clear when Austin will be released from the hospital, but said the secretary is "recovering well," adding that he expected "to resume his full duties" Friday.

The Pentagon's failure to disclose Austin's hospitalization is counter to normal practice with other senior U.S. and Cabinet officials, including the president. 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."

Iranian-backed militias have repeatedly launched drones, missiles and rockets at bases where U.S. troops are stationed in Iraq and Syria, prompting 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 Biden 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.

Ryder said this has been an "evolving situation," and due to privacy and medical issues the department did not make Austin's absence public. He declined to provide any other details about Austin's medical procedure or health.

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."

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