LAS VEGAS, Nevada — Donald Trump will make a "major announcement" Thursday about the US presidential race, according to his aides, as media reports said he will endorse Newt Gingrich.

The real estate tycoon and reality TV star, who flirted with running for the presidency himself last year, will speak in Las Vegas, a day after saying he would endorse a Republican candidate "in a very short period of time."

"I will be making a major announcement tomorrow... at Trump International Hotel & Tower, Las Vegas, Nevada. The announcement will pertain to the presidential race," he said on Twitter Wednesday.

His office would give no more details, but the news came as Republican frontrunners Mitt Romney and Newt Gingrich headed for Las Vegas ahead of the Nevada caucus on Saturday, following Tuesday's Florida primary won by Romney.

Various media reported that Trump will endorse Gingrich, who suffered a heavy defeat in Florida and faces an uphill battle to regain momentum against Romney, the long-time frontrunner who has vastly more campaign funds.

The New York Times cited a senior Gingrich official as saying Trump will endorse the former House Speaker, who campaigned in Reno, Nevada on Wednesday but was due in Las Vegas on Thursday.

Other media including the Politico website cited unidentified sources as saying Trump will endorse Gingrich at the Las Vegas announcement.

Requests for comment or confirmation from Gingrich spokespeople were not immediately returned.

In December Romney snubbed Trump by declining to participate in a debate to be hosted by the tycoon, although Trump later said that he did not resent the former Massachusetts governor's decision.

Tuesday, Trump -- whose endorsement would be a major coup for any of the four candidates still in the Republican race -- said in an ABC News television interview that he would shortly announce his decision.

"I'm friendly with both. I respect both. I like both -- They both want my endorsement," he said, referring to Romney and Gingrich. "We'll see what happens but, in a very short time I'll be making an endorsement," he added.

Trump said he would not make a third party bid if the person he endorses becomes the Republican Party's nominee to take on Democratic President Barack Obama in November.

He noted he could not run as an independent until May, because he is banned from running a presidential campaign and having a prime-time TV show -- the celebrity version of "The Apprentice," which runs until May.

In any case he would prefer to endorse a candidate than be one, he said.

"I'd rather endorse a great candidate that's going to do a great job and win the election and become a great president. That's the number one option for me," he told talk show host George Stephanopoulos.

Trump was due to arrive in Las Vegas late Wednesday night. Thursday's announcement is scheduled for 12:30 pm (2030 GMT).