United States President Joe Biden was not informed for around a month that his defense chief Lloyd Austin had prostate cancer, the White House said on Tuesday, admitting that the delay was an error.

“He was informed by the chief of staff earlier this morning,” National Security Council spokesperson John Kirby told a briefing.

Austin was diagnosed early December and underwent surgery on 22 December, before being hospitalized with complications on 1 January, the Pentagon said earlier Tuesday.

The White House was not told that the defense chief was in hospital until 4 January, at a time of high tensions in the Middle East and Ukraine.

The White House insisted that Biden, who is seeking a second term in office in elections in November, was in control of his government despite not knowing until Tuesday about the cancer diagnosis.

“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 it, or frankly other leaders at the Department of Defense,” Kirby said during a briefing at the White House.

“It’s not the way this is supposed to happen... It’s not good. We want to make sure that it doesn’t happen again.”

Biden ordered a series of military actions during that period including a strike on an Iraqi militia leader, while US forces had successfully shot down missiles fired by Yemen’s Houthi rebels in the Red Sea.

“He has been on on on top of these issues, all the way throughout,” Kirby said.