US President Joe Biden won South Carolina's Democratic primary, then vowed to make Republican rival Donald Trump a "loser" in the November election.
The 81-year-old incumbent began his march to his party's nomination with a landslide victory over two trailing rivals, according to US media projections.
But Democrats will look to the primary results to see if Biden, struggling with low approval ratings, has won back the support of black voters who helped propel him to the White House four years ago.
"Now, in 2024, the people of South Carolina have made their case again, and I have no doubt that you have put us on the path to winning the presidency again — and making Donald Trump a loser — again," Biden said.
The southern US state launched Biden's path to the White House in 2020 as he turned his campaign around after a series of setbacks in the primaries.
Biden had only two challengers: Minnesota Congressman Dean Phillips and best-selling personal development author Marian Williamson.
"Who are the other two people on the ballot? I didn't even look," joked retiree Jane Douglas, 69, as she left a polling station at an elementary school in Charleston.
Voter turnout remained low, with only a fraction of voters at polling stations, as many people apparently viewed Biden's victory as a foregone conclusion, AFP reported.
He himself urged voters to go to the polls in a video on X, saying: "South Carolina, go vote today!"
Although the state is likely to remain in Republican hands in November, as it has been since 1980, Biden saw the victory as evidence of his support among black voters.
Some of them say Biden's record as president has been mostly satisfactory. They acknowledge the lack of enthusiasm for his bid for a second term, but neither do they want to become Trump's winner.
However, a number of recent polls have shown that support for Biden is waning among black voters, especially among young people, amid frustration that he has not addressed their priorities, even though he won their support four years ago.
But other polls show him ahead of or tied with Trump, even if his personal approval ratings remain at lows not seen for a sitting president in decades.
Biden has already turned his attention to next week's Nevada primary, where he will hold a campaign event.
The Republican primary on February 24 is likely to be more dramatic than the Democratic primary. Trump will try to deliver a final blow to former South Carolina governor and UN ambassador Nikki Haley on her home turf. /BGNES