Joe Biden has been sworn in as the 46th US president at the US Capitol in Washington.
Vice-president Kamala Harris has taken her oath too - becoming the first woman to hold that position.
Democratic Senator Amy Klobuchar says in a welcome speech: "This is the day our democracy picks itself up".
Biden, 78, has become the oldest US president in history at a scaled-back ceremony in Washington that has been largely stripped of its usual pomp and circumstance, due both to the coronavirus as well as security concerns following the Jan 6 assault on the US Capitol by supporters of outgoing President Donald Trump.
With only a small number of attendees present, the Democrat took the oath of office before US Chief Justice John Roberts just afternoon (1700 GMT), placing his hand on an heirloom Bible that has been in the Biden family for more than a century.
His running mate, Kamala Harris, the daughter of immigrants from Jamaica and India, has become the first Black person, first woman and first Asian American to serve as vice president after she is sworn in by US Supreme Court Justice Sonia Sotomayor, the court’s first Latina member.
Thousands of National Guard troops were called into the city after the siege, which left five people dead and briefly forced lawmakers into hiding. Instead of a throng of supporters, the National Mall will be covered by nearly 200,000 flags and 56 pillars of light meant to represent people from US states and territories.
Biden, who has vowed to “restore the soul of America,” will call for American unity at a time of crisis in his inaugural address, according to advisers.
He will waste little time trying to turn the page on the Trump era, advisers said, signing a raft of 15 executive actions on his first day in office on issues ranging from the pandemic to the economy to climate change. The orders will include mandating masks on federal property, rejoining the Paris climate accord and ending Trump’s travel ban on some Muslim-majority countries.
In an early sign of his plan to reach across the political aisle, Biden has invited top congressional leaders, including House Republican leader Kevin McCarthy and Senate Republican leader Mitch McConnell, to join him at church on Wednesday morning.
Biden’s global leadership ambitions complicated by US Capitol riotIn a break with more than a century and a half of political tradition, Trump plans to depart the White House ahead of the inauguration, declining to meet with his successor and affirm the peaceful transfer of power.
Vice President Mike Pence, former US Presidents George W Bush, Barack Obama and Bill Clinton, and both McCarthy and McConnell are all expected to attend Biden’s inauguration ceremony.
Trump, who has grown increasingly isolated in the waning days of his tenure, has still not formally conceded the Nov 3 election. He will hold a sendoff event at Joint Air Force Base Andrews in the morning, although top Republicans, including Pence, are not expected to attend.
GRIM MILESTONES
For Biden, who long harboured presidential ambitions, the inauguration is the zenith of a five-decade career in public service that included more than three decades in the US Senate and two terms as vice president under former President Barack Obama.
But he will confront a set of overlapping crises that would challenge even someone of his political experience.
The novel coronavirus reached a pair of grim milestones on Trump’s final full day in office on Tuesday, reaching 400,000 US deaths and 24 million infections - the highest of any country. Millions of Americans are out of work because of pandemic-related shutdowns and restrictions.
Biden has vowed to bring the full weight of the federal government to bear on the crisis, including a more robust testing and tracing program and a massive vaccination drive. His top priority is a $1.9 trillion plan that would enhance jobless benefits and provide direct cash payments to households. It will require approval from a deeply divided Congress, where Democrats will hold slim advantages in both the House and Senate.
Wednesday’s executive actions, by contrast, are intended to advance Biden’s priorities without the need for legislation.
The president will establish a new White House office coordinating the coronavirus response, revoke the permit granted to the contentious Keystone XL oil pipeline and end Trump’s emergency declaration that helped fund a Mexico border wall, among other orders.
Jen Psaki, the incoming White House press secretary, said Biden plans additional executive orders in the coming weeks, including eliminating Trump’s restrictions on transgender troops and reversing a policy blocking US funds for overseas programmes linked to abortion.
Although Biden has laid out an ambitious agenda for his first 100 days, including delivering 100 million COVID-19 vaccinations, the Senate could be consumed by Trump’s upcoming impeachment trial, which will move ahead even though he has left office.
The trial could serve as an early test of Biden’s promise to foster a renewed sense of bipartisanship in Washington.