Defense Secretary Lloyd Austin was treated for prostate cancer in December, which led to a urinary tract infection and serious intestinal complications, the Pentagon said Tuesday after days of questions -- revealing details about his secretive hospitalization and the botched notification process that followed.
On Dec. 22, Austin was admitted to Walter Reed National Military Medical Center and underwent minimally invasive surgical procedure to treat and cure prostate cancer, said Maj. Gen. Pat Ryder, the Pentagon press secretary. Austin was under general anesthesia during the procedure, Ryder added.
The next day, Austin was discharged and went home, Ryder said. However, on Jan. 1, Austin was admitted again with complications from the Dec. 22 procedure determined to be a urinary tract infection.
MORE: TIMELINE: When key figures found out about Lloyd Austin's hospitalizationOn Jan. 2, Austin was transferred to the intensive care unit after an evaluation revealed abdominal fluid collections impairing the functions of small intestines, Ryder said.
"He continues to make progress and we anticipate a full recovery although this can be a slow process," Walter Reed said in a statement. "During this stay, Secretary Austin never lost consciousness and never underwent general anesthesia."
The Pentagon has come under fire for not being more transparent about information regarding Austin's hospitalization, which, until Tuesday, had been characterized as a "minor, elective procedure."
The White House learned about Austin's condition three day after he was hospitalized, and President Joe Biden was made aware of his prostate cancer diagnosis only Tuesday morning, National Security Council spokesman John Kirby said at the White House press briefing.
"Nobody at the White House knew that Secretary Austin had prostate cancer until this morning and the president was informed immediately after we were," Kirby said Tuesday.
Kirby said the White House was not made aware that Austin's authority was being transferred to Deputy Defense Secretary Kathleen Hicks while he was under general anesthesia. Hicks herself had not been informed in advance and was on vacation in Puerto Rico when Austin was hospitalized, a U.S. official told ABC News.
"It is not optimal ... for a situation like this to go as long as it did, without the commander in chief knowing about it, or the national security adviser knowing about, or frankly, other leaders at the Department of Defense. That's not the way this is supposed to happen," Kirby said.
"The president understands and, and that's why he wants the chief of staff to take a look at processes across the administration and agencies here and that's why DoD is also looking at their own procedures to make sure that that doesn't happen again."
MORE: Pentagon orders 30-day review of notification process over Secretary of Defense's hospitalizationAsked why news of Austin's prostate cancer and treatment was not shared sooner, Ryder said it's "deeply personal" for the secretary.
"As I've highlighted, it's prostate cancer and the associated procedures are obviously deeply personal, and so again, you know, we'll continue to work hard to make sure we are being as transparent as possible moving forward and again, wish the secretary a speedy recovery," Ryder said during Tuesday's press briefing.
Still at the hospital, Austin is "in contact with his senior staff and has full access to required secure communications capabilities and continues to monitor dod day-to-day operations," Ryder said.
"He continues to stay very actively engaged with his senior staff and is making important decisions about national security and defense," Ryder said.
On Monday, Ryder apologized for not being more transparent about Austin's hospitalization. Ryder said he was informed about Austin's hospitalization on Tuesday, Jan. 2 -- and two days later went to the podium for an on-camera briefing.
ABC News Senior White House Correspondent Selina Wang asked if the lack of transparency signaled a lack of trust between the White House and the Pentagon. White House press secretary Karine Jean-Pierre tried to dismiss the suggestion, saying that the White House has trust in Austin.
"We have complete confidence in the secretary. That is something that we have said. The president has complete confidence in the secretary," she said.
At about the same time as the Pentagon was detailing the news about Austin, the White House put out word it was ordering a review of Cabinet protocols for delegating authority after the fallout from Austin's undisclosed hospitalization, according to a memo obtained by ABC News.
The White House memo directs departments and agencies to submit their existing protocols for review by Jan. 12.
The memo, written by White House chief of staff Jeff Zients, says that while the review is ongoing, Cabinet agencies must adhere to procedures, including notifying the White House when agencies anticipate a delegation of authority and documenting the delegation of authority in writing.
The protocols will be reviewed to ensure they address the following: delegation criteria, decision-making authority, applicable documentation, notification procedures, and rescission of delegation.
The memo says agencies should ensure "delegations are issued when a Cabinet Member is traveling to areas with limited or no access to communication, undergoing hospitalization or a medical procedure requiring general anesthesia, or otherwise in a circumstance when he or she may be unreachable.
Within hours of Tuesday's Pentagon briefing, the Republican chairman of the House Armed Services Committee, Rep. Mike Rogers, said he had launched a formal inquiry into what had happened.
"Everything from on-going counterterrorism operations to nuclear command and control relies on a clear understanding of the Secretary’s decision-making capacity," Rogers wrote to Austin. "The Department is a robust institution, and it is designed to function under attack by our enemies, but it is not designed for a Secretary who conceals being incapacitated.”
ABC News' Lauren Peller contributed to this report.