Biden rejects Republicans' demand to sack Pentagon chief Austin

US President Joe Biden does not plan to fire Defense Secretary Lloyd Austin over his failure to disclose a hospitalisation for days, the White House said, as prominent Republicans called for the Pentagon chief to be removed.

Austin, who sits just below Biden at the top of the chain of command of the US military, withheld his multi-day hospitalisation from the president and the public for several days. He remains in the hospital, which he entered on New Year's Day.

"There is no plan for anything other than for Secretary Austin to stay in the job," John Kirby, the National Security Council spokesperson, told reporters on Air Force One Monday.

Former president Donald Trump, who is Biden's likely Republican challenger in the 2024 election, said on Sunday night that Austin should be fired for his "improper professional conduct and dereliction of duty."

"He has been missing for one week, and nobody, including his boss, Crooked Joe Biden, had a clue as to where he was, or might be," Trump wrote on Truth Social.

Another prominent Republican in Congress also called for Austin's resignation.

"There must be full accountability beginning with the immediate resignation of Secretary Austin and those that lied for him and a Congressional investigation into this dangerous dereliction of duty," Elise Stefanik, a New York representative and member of the House Armed Services Committee, which oversees the Pentagon, said in a statement.

White House press secretary Karine Jean-Pierre told reporters Biden had "complete confidence" in Austin.

"I think our main focus right now is on Secretary Austin's health and making sure that he gets all the care and support that he needs to fully recover," Kirby said, when asked about Austin's condition.

"He has already resumed all his authorities. He's already doing all of the functions he would normally do. He's just doing it right now from the hospital."

Officials disclosed on Sunday that Austin's hospitalization was kept far more secret than previously known, adding his deputy to a long list of people right up to Biden who were kept in the dark for days.

Kirby said "there was no notification or knowledge at the White House or the National Security Council until Thursday afternoon."

Austin's duties require him to be available at a moment's notice to respond to any national security crisis. He said on Saturday that he took "full responsibility" for the secrecy over his hospitalization.

What health issue spurred Austin's hospitalization is unknown. Kirby said he did not have that information, but that Biden and Austin had talked in recent days.

“It is not something that we can speak to,” Jean-Pierre said when asked about Austin’s illness, adding that the president had spoken to him on Saturday.