Biden, 80, who had delivered the commencement address to graduates of the military academy, had just shaken hands with a cadet and begun walking back to his seat when he fell.

Air Force personnel helped him back up and he did not appear to require further help.

As he rose, Biden pointed to the object that had apparently caught his foot. It resembled a small black sandbag on the stage.

White House Communications Director Ben LaBolt tweeted shortly afterward that "he's fine. There was a sandbag on stage while he was shaking hands."

Returning by Air Force One and Marine One to the White House later, Biden had another spot of bad luck: he bumped his head exiting the door of the helicopter.

He showed no sign of injury as he walked across the South Lawn and quipped to reporters that "I got sandbagged."

Biden is the oldest person ever in the presidency and is seeking a second term in the 2024 election. His official doctor's report this year declared him physically fit and he exercises regularly.

In November 2020, shortly after winning his election against the incumbent Donald Trump, Biden broke his foot while playing with a pet dog.