WASHINGTON - Sworn in as the 46th President of the United States on Wednesday (Jan 20), Mr Joe Biden encouraged a nation riven by unprecedented post-election turmoil and deep social and political divides to embrace unity.
Former senator Kamala Harris was sworn in as Vice-President, making history as the first woman, first African American and first Asian American to assume the nation's second-highest office.
"This is America's day. This is democracy's day. A day of history and hope, of renewal and resolve," said Mr Biden in his inaugural address, two weeks after a mob attacked the Capitol in an effort to overturn his victory. "At this hour, my friends, democracy has prevailed."
He called unity the key to overcoming a raging pandemic that has killed 400,000 people and battered the economy, delivering racial justice, and defeating the rise of white supremacy and domestic terrorism.
"This is our historic moment of crisis and challenge, and unity is the path forward," said Mr Biden.
He called on Americans to "reject a culture in which facts themselves are manipulated and even manufactured", and denounced lies told for power and for profit.
He also had a message of hope for a nation reeling from the ongoing pandemic and fractured by politics.
He said: "Few people in our nation's history have been more challenged or found a time more challenging or difficult than the time we're in now... To overcome these challenges, to restore the soul and secure the future of America requires so much more than words and requires the most elusive of all things in a democracy: unity."
President Biden is set to immediately roll back key policies of former president Donald Trump and will sign a raft of executive orders tackling the pandemic, climate change and immigration.
These include mandating masks on federal property, stopping America's withdrawal from the World Health Organisation, re-entering the Paris climate agreement, halting construction of a border wall and ending the travel ban on some Muslim-majority countries.
Mr Biden served as vice-president from 2009 to 2017 under then President Barack Obama, and made two previous presidential runs in his 36 years as Delaware senator.
He staged a late comeback to clinch the Democratic Party nomination and won both the electoral college and popular vote in the Nov 3 presidential election, garnering seven million more votes than Mr Trump.
About 1,000 lawmakers and guests attended the scaled-down and socially distanced ceremony, with a sea of flags on the National Mall replacing the usual crowds of hundreds of thousands who traditionally show up at inaugurations.
<p>WASHINGTON, DC - JANUARY 20: Flags line the National Mall in front of the U.S. Capitol before the start of the inauguration of U.S. President-elect Joe Biden and Vice President-elect Kamala Harris on January 20, 2021 in Washington, DC. Stephanie Keith/Getty Images/AFP
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The authorities had warned of possible domestic terrorist attacks from armed militia groups and white supremacists, as well as potentially violent pro-Trump protests.
<p>President Donald Trump speaks to supporters before boarding Air Force One for the last time at Joint Base Andrews in Maryland on Wednesday morning, Jan. 20, 2021, hours before the presidential inauguration of Joe Biden. His administration’s final acts toward China created challenges for the next phase of U.S. foreign policy. (Pete Marovich/The New York Times) </p>
PHOTO: NYTNS
<p>WEST PALM BEACH, FLORIDA - JANUARY 20: Outgoing U.S. President Donald Trump and First Lady Melania Trump exit Air Force One at the Palm Beach International Airport on the way to Mar-a-Lago Club on January 20, 2020 in West Palm Beach, Florida. Trump left Washington, DC on the last day of his administration before Joe Biden was sworn-in as the 46th president of the United States. Noam Galai/Getty Images/AFP
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PHOTO: GETTY IMAGES NORTH AMERICA
Mr Trump continued to deny that he had lost the elections, continuing to tell his supporters for weeks that it had been stolen from him.