South Carolina primary: Donald Trump easily defeats Nikki Haley in her home state

The former president won his primary opponent's home state by a 20-point margin, his fourth consecutive victory.

As he celebrated Mr Trump made no mention of Ms Haley, who vowed to stay in the race. Instead he set his sights on the general election in November.

That will be a likely rematch with his successor in the White House.

"We're going to look Joe Biden right in the eye," he told supporters minutes after US media projected him as the winner on Saturday night. "He's destroying our country - and we're going to say 'get out Joe, you're fired'."

Mr Trump lauded his party's "unity" after Saturday's result, saying: "There's never been a spirit like this. I have never seen the Republican Party so unified."

It marked a shift from his response to last month's primary in New Hampshire, where he raged against Ms Haley for "doing a speech like she won".

Ms Haley, who once served as a popular two-term governor of South Carolina, congratulated her opponent on his victory in her speech.

She promised not to quit, however, saying the roughly 40% of the vote she received was "not some tiny group".

"There are huge numbers of voters in our Republican primaries who are saying they want an alternative," she said, emphasising that her continued campaign was not about her own political ambitions.

"I'm not giving up this fight when a majority of Americans disapprove of both Donald Trump and Joe Biden," she added.

She has re-committed to staying in the race until at least Super Tuesday - 5 March - when voters in 16 states will cast their ballots on the same day.

"I'm a woman of my word," the former UN ambassador said. "We're headed to Michigan tomorrow, and we're headed to the Super Tuesday states throughout all of next week."

The Trump campaign dismissed Ms Haley's continued effort in a statement on Saturday, stating that her "delusion is clouding her judgement, and she is no longer living in reality".

The Trump campaign has predicted the former president will accumulate enough delegates to formally clinch the nomination within the next month.

Ms Haley does not have a clear path forward - her opponent has a large lead in the delegate count and is polling far ahead in all future contests.

And yet the Haley campaign is still standing, in large part due to contributions from deep-pocketed donors. That flow of cash has continued despite her facing long odds.

Ms Haley raised $16.5m in January alone, campaign officials said. That was her largest monthly total so far, and much more than Mr Trump's numbers.

To drive home the point that he believes the primary has now ended, Mr Trump wasted no time in making his victory speech moments after the race was called, not allowing Ms Haley to speak before him as she had done in New Hampshire.

Flanked at his podium on the Columbia state fairgrounds by nearly two dozen allies, including most of the state's political leaders, he told a raucous crowd: "This was a little sooner than we anticipated."

Mr Trump certainly has much to boast about with this win. Exit polling conducted by the BBC's US partner, CBS News, shows that the ex-president bested Ms Haley with both men and women, and among all age groups.

Lauding them for their support, Mr Trump, 77, reminded his audience: "We have a lot of work ahead of us."

The former president also remains beleaguered by his many legal troubles, and faces the first of four criminal trials next month.

He is also now on the hook for more than half a billion dollars, the combined total of two recent civil trial rulings against him in New York - one for sexual assault and defamation, and another for business fraud.

As Mr Biden racks up a sizeable cash advantage over him in what will likely be the most expensive presidential race in US history, Mr Trump is increasingly relying on donations to cover his soaring legal costs.

It appears the Republican Party could come to his aid. He has consolidated his hold over it by endorsing key allies to lead its national committee.

His daughter-in-law Lara Trump, his pick to take over as co-chair of the Republican Party, has pledged to "spend every penny" of party funds on his legal defence.

-bbc