Washington DC - Presidential hopeful Nikki Haley drew nasty taunts from former President Donald Trump on Friday in a sign she is gaining some traction in the still one-sided Republican presidential race.

Trump derided Haley as a "birdbrain" and vowed that neither he nor his loyal supporters would back his former UN ambassador for the White House or any other position.

"MAGA, or I, will never go for Birdbrain Nikki Haley," Trump wrote. "No loyalty, plenty of lies!"

Trump accused Haley of reneging on a promise to support his comeback White House bid.

Donald Trump Does Donald Trump have his eyes on a new running mate?

"Her words mean nothing. She even came to Mar-a-Lago with her family," Trump said. "Anyway, (Haley) doesn't have the TALENT or TEMPERAMENT to do the job."

The attacks came two days after Haley — who's routinely called out the former president — put in a second strong performance in the Republican debate, offering memorable rhetorical zingers. A poll by FiveThirtyEight taken after the second debate showed Haley delivered an above-average performance.

The attack from Trump may be a sign that the former president also sees her as a potentially potent rival.

Trump, who holds a commanding lead over all comers in the Republican race, has spent months relentlessly attacking Florida Governor Ron DeSantis.

The single-minded focus on DeSantis reflected the widespread belief in Trumpworld that he posed the only credible threat to Trump winning the Republican nomination. DeSantis briefly led some Republican polls after his historic landslide Florida reelection victory in the midterms. But he has been locked in a seemingly irreversible slide since then.

That dynamic has forced Republican mega-donors who oppose Trump to cast their net further afield, with Haley looking like the new flavor of the month candidate.

Some donors are calling on officials in the DeSantis and Haley campaigns to make countering pitches to donors at an October 13 confab in Dallas.