Joe Biden is to be sworn in as US president, taking the helm of a nation wracked by political division, economic anguish and an unrelenting pandemic.

Vice-President-elect Kamala Harris will take the oath of office alongside him in Washington DC, which has been fortified amid fears of civil unrest.

Some 25,000 troops will guard the inauguration ceremony after a deadly riot at the Capitol earlier this month.

Donald Trump will leave the White House for the last time, bound for Florida.