Donald Trump maintains a lead in every other state, charging towards the Republican nomination.
Former US ambassador Nikki Haley is expected to end her primary bid leaving Donald Trump as the sole Republican candidate for the presidential nomination, local media reported Wednesday.
She is expected to announce her decision in a speech around 15:00 GMT on Wednesday, from South Carolina state capital Charleston, where she served as governor, the Wall Street Journal and CNN reported citing sources.
The withdrawal from the race comes after the US leader scored a surprising victory over Donald Trump in the Republican primary in the US state of Vermont, her second win in the race for the White House in 2024.
Donald Trump, 77, maintains a lead in every other state, charging towards the Republican nomination. He celebrated an "amazing night" as he closed in on the Republican presidential nomination with easy wins in the Super Tuesday primaries, setting up an all-but-certain rematch with President Joe Biden in November.
Haley -- a favourite of affluent, suburban voters and university graduates -- was set to collect only a handful of the delegates needed to secure the nomination.
Former president Trump swept 14 out of 15 states up for grabs on the biggest day of the 2024 race so far, with Haley denying him only in the northeastern state of Vermont as he covets a second term in the Oval Office.
Incumbent Biden also swept the Democratic "Super Tuesday" primaries, although he was effectively uncontested, and the 81-year-old will now turn his attention to his crucial State of the Union speech on Thursday.
Eyeing a historic comeback to the US presidency, Trump told cheering supporters at his Mar-a-Lago beach club in Florida that they had witnessed "an amazing night and an amazing day."
"They call it 'Super Tuesday' for a reason," said Trump, 77.
"This is a big one. They tell me, the pundits and otherwise, that there has never been one like this, never been anything so conclusive."
Haley, a former South Carolina governor, has failed to throw significant obstacles in Trump's path to the nomination since finishing a distant third in the opening contest in Iowa in January.
Impeached twice, beaten by seven million votes in 2020 and facing 91 felony charges in four trials, Trump has a profile unlike any US presidential election candidate in history.
Yet his appeal among working-class, rural and white voters, particularly on issues like immigration and the economy, has propelled him toward the nomination in one of the most lopsided primary seasons ever seen.