US President has tripped and fallen while handing out diplomas at a graduation ceremony for the US Air Force Academy in Colorado, writes BBC.

Joe Biden, who is the nation’s oldest serving president at 80, was helped back up to his feet and appeared to be unhurt. He had been standing for about an hour and a half to shake hands with each of the 921 graduating cadets.

The White House communications director said earlier “he’s fine”. “There was a sandbag on stage while he was shaking hands”, - tweeted Ben LaBolt. “I got sandbagged”, - the smiling president joked to reporters as he arrived back at the White House that evening.

A White House press pool report earlier said Biden had tripped on a black sandbag while moving on stage.