US Defense Secretary Lloyd Austin was hospitalized earlier this week due to complications from a medical procedure, the Pentagon said Friday, at a time when Washington is facing a growing crisis in the Middle East.

Austin was admitted to Walter Reed National Military Medical Center on the evening of January 1 "for complications following a recent elective medical procedure," Pentagon Press Secretary Major General Pat Ryder said in a statement, without providing details on the complications or the duration of the hospital stay.

"He is recovering well and is expecting to resume his full duties today," Ryder said.

For several days, both Congress members and leaders within the Pentagon were unaware that Austin had been hospitalized since Monday, the Associated Press reported citing US officials. This lack of knowledge prompted queries about the Pentagon chief's condition and the confidentiality surrounding it.

Ryder mentioned that the White House and the Joint Chiefs of Staff were informed about Austin's hospitalization. However, he did not disclose the timing of this notification.

According to a number of US officials, several high-ranking Pentagon officials reportedly only became aware of Austin's hospitalization on Friday. The officials mentioned that US President Joe Biden and key White House personnel were briefed earlier, though the exact timing wasn't revealed.

Ryder confirmed that members of Congress were notified of Austin's hospitalization late on Friday afternoon, while other officials mentioned it was after 5 p.m., AP indicated.

The Associated Press revealed that many Pentagon staff learned about Austin's hospital stay from the department's official statement, released just after 5 p.m., adding that some had presumed Austin was on vacation for the week.

Ryder on Friday cited privacy and medical concerns as reasons why the Pentagon hadn't publicized Austin's absence.

The Defense Department had not previously disclosed that Austin was hospitalized, with Friday's announcement prompting criticism from the Pentagon Press Association.

In a letter to the Pentagon press secretary expressing "significant concerns," the press association said withholding the announcement for days until "late on a Friday evening is an outrage."

"The public has a right to know when US Cabinet members are hospitalized, under anesthesia or when duties are delegated as a result of any medical procedure," said the letter from the association, made up of journalists that cover the Pentagon.