WASHINGTON — Defense Secretary Lloyd Austin was diagnosed with prostate cancer in December and developed complications from a minimally invasive procedure he underwent to treat and cure it, officials from Walter Reed National Military Center officials said Tuesday.

The complications are what led to Austin being admitted to Walter Reed on Jan. 1, and eventually, the intensive care unit. Austin remained in the hospital on Tuesday.

The Pentagon took three days to inform the White House and key defense officials about Austin’s hospitalization, prompting criticism and triggering a review of procedures about how the head of the military could be away from his duties for so long without senior members of the administration knowing.

President Joe Biden and other top White House officials learned about his hospitalization on Thursday, but National Security Council spokesman John Kirby told reporters Tuesday that neither Biden nor anyone at the White House knew about Austin’s cancer diagnosis until Tuesday morning, hours before Walter Reed officials made that information public.

The cancer was discovered in early December in routine lab tests for prostate screening, Walter Reed officials said. The surgical procedure Austin underwent on Dec. 22 was a prostatectomy, and Austin was “under general anesthesia” during it.

“Secretary Austin recovered uneventfully from his surgery and returned home the next morning. His prostate cancer was detected early, and his prognosis is excellent,” the officials said.

Austin, 70, was then admitted to Walter Reed on Jan. 1 “with complications from the December 22 procedure, including nausea with severe abdominal, hip, and leg pain,” the officials said.

An initial evaluation found that he had a urinary tract infection and on Jan. 2, a decision was made to transfer Austin to the intensive care unit for “close monitoring and a higher level of care,” the statement said.

Doctors then discovered that Austin had “abdominal fluid collections impairing the function of his small intestines.”

“This resulted in the back up of his intestinal contents which was treated by placing a tube through his nose to drain his stomach,” the officials added. “The abdominal fluid collections were drained by non-surgical drain placement. He has progressed steadily throughout his stay.”

Officials said in the statement Tuesday that Austin’s “infection has cleared” and “he continues to make progress and we anticipate a full recovery although this can be a slow process.” They said that during his subsequent hospitalization, Austin “never lost consciousness and never underwent general anesthesia.”

At a press briefing Tuesday immediately after the statement was released, Pentagon press secretary Maj. Gen. Pat Ryder told reporters that the secretary “continues to recover well and is in good spirits.” He said the department will be releasing daily status updates about his condition. Ryder said he has not spoken with Austin and did not know why he hadn’t shared details about his illness earlier, but called prostate cancer and its treatments “deeply personal.”

When asked if Austin would have to take a step back from his duties as defense chief such as a rigorous travel schedule, Ryder said Austin “continues to monitor DoD’s operations worldwide” and “is actively engaged in his duties.”

Ryder said that Austin is “not resigning” and Kirby said at Tuesday’s White House briefing that Biden plans to stick with Austin through the rest of his presidential term.

The revelation about Austin’s condition is a new development after the defense secretary and several of his aides waited days to notify the White House and key Pentagon officials that he was hospitalized for complications following what was described as “an elective medical procedure.”

The public didn’t know he was hospitalized until Friday evening when Ryder released a statement saying that Austin had been admitted to the Walter Reed National Military Medical Center on Monday night for “complications following a recent elective medical procedure,” though he didn’t specify what the procedure was.

The Defense Department didn’t tell senior officials at the National Security Council about the secretary’s hospitalization until Thursday.

Last Tuesday, a day after he was admitted, some of the secretary’s duties were transferred to Deputy Secretary of Defense Kathleen Hicks who was on vacation in Puerto Rico. She was not told, however, about Austin’s hospitalization until Thursday, a senior defense official said Sunday.

On Monday, Ryder told reporters that he was informed about Austin’s hospitalization on Jan. 2, a day after he was admitted and two days before Biden and national security adviser Jake Sullivan were told. Ryder briefed reporters on camera on Thursday and did not disclose the secretary’s continued hospitalization. He did not provide further details — including whether he was directed not to tell anyone.

Ryder also said Monday that the Pentagon’s lawyers were reviewing whether any laws were broken during this failure to notify U.S. leaders and Congress.

House Armed Services Committee Chairman Mike Rogers on Tuesday announced a formal inquiry into the lack of transparency surrounding Austin’s hospitalization.

The Alabama Republican said he wants Pentagon officials to provide details on any medical sedation or general anesthesia Austin received, in addition to any instructions not to inform people about his hospitalization and any official acts he performed during this period. Rogers is also asking Hicks and Austin’s chief of staff for specific details about what they knew and when, as well as their actions during that time.

Austin’s diagnosis and subsequent hospitalization occurred as tensions continued to intensify in the Middle East, including a rare and controversial strike by the U.S. against a senior Iranian-backed militia member in Baghdad.

The statement from Walter Reed noted that prostate cancer is the most common cause of cancer among American men, affecting 1 in every 8 men and 1 in every 6 Black men.