Donald Trump's crushing presidential victory heralded a new era of uncertainty in the United States and the world Wednesday, as defeated Kamala Harris gave a defiant concession speech while vowing to help his transition to power.
An emotional Vice President Harris told tearful supporters in a speech in Washington to "not despair," urging them to "keep fighting" after her loss.
Her pledge to ensure a peaceful handover stood in stark contrast with Republican Trump's unprecedented refusal four years ago to admit defeat against Joe Biden, culminating in the violent attack by his supporters on the US Capitol.
"While I concede this election, I do not concede the fight that fueled this campaign," Harris said in her short, powerful speech at Howard University, her alma mater.
"I know many people feel like we are entering a dark time," she said, her voice hoarse as she made her first public remarks since Trump's surprisingly heavy victory. "But for the benefit of us all, I hope that's not the case."
Harris - who had blasted Trump as a threat to democracy during her failed bid to become America's first woman president - earlier called him to offer her congratulations, an aide said.
Trump sealed his historic comeback to the White House overnight, cementing what is set to be more than a decade of US politics overshadowed by his hardline, disruptive right-wing politics.
The 78-year-old won wider margins than before, despite a criminal conviction, two impeachments while in office and warnings from his former chief of staff that he is a fascist.
Exit polls showed that voters' top concern remained the economy and inflation that spiked under Biden in the wake of the Covid pandemic.
Harris had also hoped for a surge in support from women, but CNN exit polls gave her only an eight-point advantage among the demographic, nearly half what Joe Biden mustered four years ago.
'Price of groceries'
Biden, 81, who dropped out of the race in July over concerns about his age, invited Trump to the White House, officials said.
Trump accepted and "looks forward to the meeting, which will take place shortly," the president-elect's spokesman Steven Cheung said.
Biden will address the nation on Thursday and paid tribute to Harris for her "courage" and "integrity."
Both Wall Street and the dollar soared on Trump's victory, with expectations that he will move aggressively to ramp up economic growth.
Trump, who will be the oldest person ever to take the presidential oath when inaugurated on January 20, vowed to fulfill his slogan to "Make America Great Again" in a speech in the early hours of Wednesday in Florida.
"It's a political victory that our country has never seen before," Trump said.
In Phoenix, Arizona, Jimmy Archuleta, a 47-year-old auto worker, hailed Trump as "a genius businessman."
"I just hope he'll make the price of groceries and gas more reasonable," Archuleta told AFP.
Global leaders swiftly pledged to work with Trump, despite concerns in much of the world about his nationalist-minded "America First" approach.
Ukrainian President Volodymyr Zelensky, whose country was invaded by Russia in 2022, said he congratulated Trump in an "excellent" call on Wednesday.
Trump and Vice President-elect J.D. Vance oppose the billions of dollars in US assistance to Kyiv under Biden and they are expected to force Ukraine into making concessions to Moscow.
One leader certain to be pleased was Israeli Prime Minister Benjamin Netanyahu, a Trump ally who could now get freer rein to execute his war against Hamas in Gaza.
Change and turmoil
Harris ran a centrist campaign that highlighted Trump's inflammatory messaging and constant use of racist and sexist tropes in his speeches.
But Trump's often apocalyptic warnings about illegal immigration found their mark with voters battered by the post-Covid economy and eager for change after the Biden years.
Hispanic and Black Americans, seen as crucial Democratic voting blocs, moved in greater numbers toward Trump, who won a majority of Latino men, exit polls showed.
Opinion polls had predicted a nail-bitingly close contest - yet the results came surprisingly quickly, including Trump's flipping of the swing states Georgia, Pennsylvania, Wisconsin and Michigan that Biden won four years ago.
Trump appeared on track to win the popular vote for the first time, and the Republican Party also won the Senate from the Democrats, boosting his ability to enact his agenda.
Trump is the second president ever to win a non-consecutive term and the only to be elected as a convicted felon - he is scheduled to face sentencing in a New York court for fraud on November 26.
His campaign pledges, if carried out, could cause turmoil, especially his vow to deport millions of undocumented immigrants.
Trump is also a longtime sceptic of climate change who is expected again to reduce US global commitments, although one of his top campaign surrogates was fellow brash billionaire Elon Musk, owner of electric vehicle maker Tesla.