Donald Trump has left the White House for the last time as president with a vow to stay in the spotlight.
He gave an extraordinary snub to Joe Biden, by skipping his inauguration as the 46th president of the United States.
Drawing a curtain on the most tumultuous administration of modern times, Trump is being ousted by a polar opposite with the Democrat Biden intent on charting a new course to tackle Covid-19 and unite a splintered nation.
Trump, 74, and first lady Melania Trump walked a short red carpet and boarded the Marine One helicopter, which flew near the Capitol that was ready for Biden's inauguration before heading to Andrews Air Force Base on Washington's outskirts.
"This has been an incredible four years," Trump told several hundred cheering supporters in a campaign-style event before flying off for the last time in Air Force One en route to his Florida resort.
"We will be back in some form," vowed Trump, who retains a hold on much of the Republican Party despite being the first president to be impeached twice.
Trump -- who for two months has falsely alleged election fraud -- did not address Biden by name but, in a rare hint of graciousness, wished the next administration "great luck and great success."
While a spokesman said the president had left a letter for Biden, Trump is the first sitting president since 1869 to skip the inauguration of his successor.
Inauguration
Biden and Vice President-elect Kamala Harris will take the oath of office at noon (1700 GMT) at the very spot where pro-Trump rioters clashed with police two weeks ago before storming Congress in a deadly insurrection.
Official Washington has taken on the dystopian look of an armed camp, protected by some 25,000 National Guard troops tasked with preventing any repeat of this month's attack.
And with the pandemic raging, the general public is essentially barred from attending the swearing-in, leading to the unprecedented sight of an empty National Mall on Inauguration Day.
With the death toll soaring past 400,000, Biden led a powerful tribute to victims of Covid-19 as he arrived in Washington on the eve of his swearing-in.
"It's hard sometimes to remember, but that's how we heal. It's important to do that as a nation," Biden said in somber remarks in front of the Lincoln Memorial, once more stressing the need to unite the country after Trump's chaos.
On the Mall's grassy expanse, some 200,000 flags have been planted to represent the absent crowds at the inauguration.
'I'll get right to work'
"We don't have a second to waste when it comes to tackling the crises we face as a nation," Biden tweeted late Tuesday.
"That's why after being sworn in tomorrow, I'll get right to work."
He plans to kick off his tenure by rejoining the Paris climate accord and the World Health Organization, according to aides, who said Biden would sign 17 orders and actions just hours after being sworn in, setting new paths on immigration, the environment, Covid-19 and the economy.
In first-day moves, he will end Trump's much-assailed ban on visitors from several majority-Muslim countries and halt construction of the wall that Trump ordered on the US-Mexico border to stem illegal immigration, the aides said.
To symbolise the new spirit of unity, Biden -- a senator for 36 years -- headed before his inauguration to a church service with the congressional leaders including the two top senators -- Democrat Chuck Schumer and Republican Mitch McConnell.
