WASHINGTON (REUTERS, NYTIMES, BLOOMBERG) - Ms Kamala Harris was sworn in as Vice-President of the United States on Wednesday (Jan 20), becoming the first woman, the first black person and the first Asian American to hold the office.

The former California senator, 56, took the oath of office from Supreme Court Justice Sonia Sotomayor in a ceremony at the US Capitol.

To mark the special occasion, she opted for a brilliant purple coat - a design by Mr Christopher John Rogers, the 2020 CFDA American Emerging Designer of the Year.

Mr Rogers, 27, is young, black and a rising star in American fashion, Harper's Bazaar reported.

The colour purple is traditionally seen in the US as a symbol of bipartisanship - a combination of the blue and red of the Democratic and Republican parties, respectively.

"For the people - always," Ms Harris tweeted at the inauguration.

At the swearing-in ceremony, Lady Gaga sang the national anthem while Jennifer Lopez and Garth Brooks also performed.

Shortly after Ms Harris was sworn in as Vice-President, Mr Joe Biden was sworn in as the 46th President of the United States.

The ceremony took place in a barricaded city, guarded by more than 25,000 troops and emptied of the spectators who usually throng the quadrennial ritual.

The unprecedented precautions, which fenced off much of downtown Washington, ensured that Mr Biden and Ms Harris took their oaths free of incident.

Some right-wing extremist groups had earlier vowed to disrupt Mr Biden's inauguration in the wake of a Jan 6 attack on the US Capitol that left five people dead, including a Capitol Police officer.

Earlier on Wednesday morning, outgoing President Donald Trump left the White House for the final time, his helicopter flying over thousands of American and state flags planted on the National Mall. The banners stood in for the hundreds of thousands of people who would gather for past inaugurations to watch the proceedings on big-screen televisions.

A handful of visitors lingered outside Union Station, the city's normally bustling train terminal.

"I'm looking forward to some change and cautiously optimistic," said Mr Victor Duran, 22, a student from Dallas.

National Guard troops, carrying rifles, stood behind razor-wire-topped fencing that sealed off Capitol Hill. Motorcades carrying VIPs sped past.

A small group of protesters stood outside the perimeter.

"If Joe Biden wants to take America to hell, go right ahead!" one shouted through a bullhorn.

Two demonstrations that had been planned along the parade route between the Capitol and the White House were cancelled, according to the National Park Service.

The security precautions, along with a coronavirus pandemic that has prompted many to avoid public gatherings, left city streets largely empty in the nation's capital.

"It's, frankly, painful to see this, the whole city shut down," former Republican senator Jeff Flake told reporters as he arrived at the Capitol.

Bridges between Virginia and downtown Washington were closed, as were downtown metro stations.

With inaugural balls and other parties cancelled due to the pandemic, the event has taken on a sombre tone in Washington.

The 128-year-old house at Number One Observatory Circle will be the designated home where Ms Harris and her husband Doug Emhoff are set to live for at least the next four years.

Located about 3km from the White House and adjacent to several embassies, the secluded home sits on a 29ha plot known as the US Naval Observatory.