Defense Secretary Lloyd Austin is expected to resume his duties on Tuesday after undergoing "non-surgical procedures" to address a bladder issue, doctors with Walter Reed National Military Medical Center said in a statement on Monday. 

Austin was hospitalized on Sunday for the second time due to complications from a procedure to treat prostate cancer in December.

"Secretary of Defense Lloyd J. Austin III underwent non-surgical procedures under general anesthesia to address his bladder issue," doctors with Walter Reed said in a statement released by the Pentagon. "We anticipate a successful recovery and will closely monitor him overnight."

"A prolonged hospital stay is not anticipated," the statement from the doctors continues, adding that they "anticipate" he will be able to resume his duties on Tuesday. "The current bladder issue is not expected to change his anticipated full recovery. His cancer prognosis remains excellent."

The chairman of the Joint Chiefs of Staff was notified of his Sunday hospitalization, as well as the White House and Congress.

Pentagon spokesperson Maj. Gen. Patrick Ryder said “to my knowledge,” Austin had not spoken to President Joe Biden since his hospitalization as of Monday afternoon. Earlier on Monday, White House national security spokesman John Kirby said he did not know if President Joe Biden had spoken directly to Austin since he was hospitalized on Sunday but that the president still had confidence in his ability to serve.

Austin did not tell Biden, Congress or his deputy defense secretary of his December cancer diagnosis or initial hospitalization for weeks. That secrecy has become the subject of an inspector general investigation and a Pentagon internal review. He has previously said he never instructed his staff to keep his hospitalization a secret.

He canceled his trip to Brussels this week to meet with NATO ministers and work on Ukraine military aid amid his hospitalization, Ryder said.

Austin had been scheduled to travel to Brussels on Tuesday to attend a regular meeting of the Ukraine Defense Contact Group, a gathering of about 50 countries to coordinate military aid for Kyiv. That meeting will now be held virtually, according to Ryder. And U.S. Permanent Representative to NATO Julie Smith will attend a NATO defense meeting on Thursday in Austin’s place.

At about 2:20 p.m. Sunday, Austin, 70, was transported by his security detail to Walter Reed National Military Medical Center "to be seen for symptoms suggesting an emergent bladder issue," Ryder said in a statement hours later. After further tests he was admitted into the critical care unit for supportive care and close monitoring and has since transferred authorities to Deputy Defense Secretary Kathleen Hicks.

While Austin initially intended to retain the "functions and duties of his office,” at about 5 p.m. Sunday he transferred those authorities to Deputy Secretary of Defense Kathleen Hicks. Austin is sixth in the presidential line of succession and Ryder could not say on Monday if Hicks would assume his position. Acting secretaries are typically not included in the presidential line of succession, but Biden recently added Acting Labor Secretary Julie Su, who has yet to be confirmed by the Senate.

A statement from Walter Reed medical officials late Sunday said Austin was admitted into the critical care unit for supportive care and close monitoring. Dr. John Maddox, the trauma medical director, and Dr. Gregory Chesnut, director of the Center for Prostate Disease Research of the Murtha Cancer Center, said while it was unclear at this time how long Austin will remain hospitalized, “the current bladder issue is not expected to change his anticipated full recovery.”

Austin was diagnosed with prostate cancer in December and underwent a procedure called a prostatectomy to treat it on Dec. 22.

Over the following week, he developed complications and on Jan. 1, in extreme pain, he was taken to Walter Reed by ambulance where he was admitted to the intensive care unit. Austin remained at Walter Reed until Jan. 15. He then continued to recover and work from home, and he returned to the Pentagon Jan. 29.

His doctors have previously said his prognosis against the cancer is “excellent” and that no further treatments will be needed.

Austin has gone back to Walter Reed for follow-ups since his hospitalization but this is his first unscheduled trip due to continued complications from his cancer treatments.