WASHINGTON: Former UN ambassador Nikki Haley on Wednesday previewed a "big announcement" she plans to make in two weeks, widely expected to be the launch of her 2024 US presidential run - making her the first Republican to throw down the gauntlet to Donald Trump in the race for the White House.

"My family and I have a big announcement to share with you on February 15th! And yes, it's definitely going to be a Great Day in South Carolina!," she tweeted.

Casting herself as a younger, fresher alternative to the former president, Haley has been hinting at a White House bid for weeks, recently posting a video on social media in which she declared: "It's time for a new generation to lead."

The 51-year-old, who served for six years as the governor of South Carolina, is expected to officially announce at an event in Charleston, the Palmetto State's largest town, on February 15.

At this point in the 2020 cycle, 10 Democrats had launched campaigns or exploratory committees, but Trump is so far the only Republican to do so this time around.

Haley, who was Trump's United Nations ambassador for two years, had said she wouldn't run against her former boss.

But her announcement would confirm that Trump will not run uncontested, and Haley is unlikely to be the last Republican to throw their hat in the ring.

Other Republicans seen as potential rivals to Trump include Florida Governor Ron DeSantis, Trump's vice president Mike Pence and secretary of state Mike Pompeo, and former Maryland governor Larry Hogan.

"It's exciting to see the leadership that's coming out of South Carolina," said Nancy Mace, a rare anti-Trump House Republican, at a political event in Washington on Wednesday, confirming that she was expecting an invitation to Haley's announcement by the end of the day.

She didn't confirm whether she would be attending, however, telling the crowd at the event organized by congressional media outlet Axios that she was "looking at" possibly endorsing Haley.

Trump said on his way to a rally Saturday in South Carolina's capital, Columbia, that he had spoken to his former envoy on the phone and had encouraged her to run.

The daughter of Indian immigrants, Nimrata "Nikki" Randhawa was raised in Bamberg, South Carolina as a Sikh, but now identifies as Christian. She is married to a South Carolina National Guard officer and has two children.

She rose quickly in the southern state's politics, building a reputation as a plain-spoken conservative in its House of Representatives from 2005 to 2011, when she was elected governor.

She was the face of diversity in a cabinet criticized for being too white, and left the administration in 2018 with a strong global profile - and a reputation for standing up to her mercurial boss.

But Haley's messaging on Trump has always been inconsistent.

She endorsed senators Marco Rubio and Ted Cruz during the 2016 Republican presidential primary, calling the brash property baron "everything a governor doesn't want in a president."

Since leaving government, her praise of the Trump presidency has been offset by her criticism of his personal conduct, including his involvement in the 2021 attack on the US Capitol.

Haley averages three percent in 2024 primary opinion polls, according to Morning Consult, trailing far behind Trump at 48 percent, DeSantis at 31 percent, and Pence in single digits.

North Carolina Senator Thom Tillis said at the Axios event elected officials in Washington are "not particularly popular" in a polarized America yearning for change.

"I think President Trump needs to come before the American people, like others that are going to enter in the primary, and build a case," he said.

"People are asking me am I picking somebody at this point. I say, my goodness, it's February of 2023. I want to hear the case."

 - AFP