U.S. Department of Defense Secretary Lloyd Austin was hospitalized on Sunday for "symptoms suggesting an emergent bladder issue," officials have revealed.

"Earlier today, Secretary of Defense Lloyd J. Austin III was transported by his security detail to Walter Reed National Military Medical Center to be seen for symptoms suggesting an emergent bladder issue," Dr John Maddox, trauma medical director, and Dr Gregory Chesnut, director of the Center for Prostate Disease Research of the Murtha Cancer Center, said in a statement.

Defense Secretary Lloyd Austin transferred his duties to his deputy as he is hospitalized for treatment for symptoms “suggesting an emergent bladder issue,” according to the Pentagon.

Austin has been admitted into the critical care unit at Walter Reed National Military Medical Center, and it is “not clear how long Secretary Austin will remain hospitalized,” according to a statement released Sunday night from officials at the hospital.

U.S. Secretary of Defense Lloyd Austin was taken to a Washington, D.C. hospital on Sunday for treatment of "symptoms suggesting an emergent bladder issue", a Pentagon spokesman said.

Austin, 70, was retaining his duties during his hospitalization, Pentagon Press Secretary Maj. Gen. Pat Ryder said in a written statement.

Austin was criticized last month for failing to disclose a cancer diagnosis and subsequent hospitalizations in December and January, including to President Joe Biden. He apologized during a televised news briefing.

U.S. officials have confirmed to CBS News that plans have been approved for a series of strikes over a number of days against targets — including Iranian personnel and facilities — inside Iraq and Syria. The strikes will come in response to drone and rocket attacks targeting U.S. forces in the region, including the drone attack on Sunday that killed three U.S. service members at the Tower 22 base inside Jordan, near the Syrian border.

The Iranian-backed terrorists responsible for murdering three U.S. soldiers, and injuring dozens more, in an attack over the weekend have started to evacuate their bases after President Joe Biden’s administration leaked to the media this week that they are gearing up to respond by carrying out a sustained bombing campaign.

The news comes after NBC News reported on Wednesday that the U.S. retaliatory strikes would be a “campaign” that lasts “weeks,” according to U.S. officials.

The planned targets for U.S. strikes in Iraq and Syria in response to the killing of three U.S. soldiers by a drone in Jordan include "Iranian personnel and facilities", CBS News reported on Thursday, citing American officials.

The United States has assessed that the drone, which also wounded more than 40 people, was made by Iran, four U.S. officials told Reuters. Sources said Iran's elite Revolutionary Guards were pulling senior officers out of Syria.

Defense Secretary Lloyd Austin apologized for keeping his recent hospitalization hidden from the White House and the American people.

"We did not handle this right. I did not handle this right," he told reporters Thursday in his first news conference since his secret hospitalization and since the deadly drone attack in Jordan that killed three American soldiers.