Republican front-runner Donald Trump on Tuesday bowed out of the final Republican presidential debate before the leadoff Iowa caucuses, saying Fox News moderator Megyn Kelly is "a lightweight."

With 48 hours to go before the faceoff, campaign manager Corey Lewandowski confirmed Trump's decision Tuesday evening after a press conference in which Trump lashed out at Kelly and said she'd been "toying" with him.

"He will not be participating in the Fox News debate Thursday," Lewandowski said immediately after the press conference.

Trump, who called his decision "pretty close to irrevocable" in the press conference, said he'd hold an Iowa event at the same time as the debate to raise money for wounded veterans. Iowa hosts the nation's opening presidential nominating contest on Monday.

"With me, they're dealing with somebody that's a little bit different. They can't toy with me like they toy with everybody else," he said. "Let them have their debate and let's see how they do with the ratings."

He added, "Why do I have to make Fox rich?"

On Tuesday night's airing of her Fox News show, The Kelly File, Kelly said she'll be at the debate, which will "go on with or without Mr. Trump."

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Megyn Kelly had moderated a previous Republican debate in August of 2015. (Richard Drew/Associated Press)

In a statement released Tuesday night, a Fox News spokesperson said Trump is still welcome to participate in the debate, but will not be allowed to "dictate the moderators or the questions."

"Capitulating to politicians' ultimatums about a debate moderator violates all journalistic standards," Fox said.

The Republican National Committee said the decision was up to Trump.

"Obviously we would love all of the candidates to participate but each campaign ultimately makes their own decision what's in their best interest," said RNC chief strategist Sean Spicer.

And then there were 7?

Trump had suggested he might skip the Fox debate earlier in the day, drawing a sarcastic statement from the television network that "the Ayatollah and Putin both intend to treat Donald Trump unfairly when they meet with him if he becomes president."

"A nefarious source tells us that Trump has his own secret plan to replace the Cabinet with his Twitter followers to see if he should even go to those meetings," the Fox statement said.

A Fox spokesman did not immediately respond to Trump's decision.

The New York real estate mogul's presence has helped produce massive ratings in the previous six Republican presidential debates. His decision leaves seven candidates to share the primetime stage on Thursday: Texas Sen. Ted Cruz, Florida Sen. Marco Rubio, retired neurosurgeon Ben Carson, former Florida Gov. Jeb Bush, New Jersey Gov. Chris Christie, Ohio Gov. John Kasich and Kentucky Sen. Rand Paul.

"Let them have their debate. I'm going to raise money during that period of time for the wounded warriors and for the vets. Let Fox play its games," Trump said.

He added, "I don't' think Iowa's gonna care."

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Ted Cruz, right, says Donald Trump owes it to Iowa voters to debate. (Rainier Ehrhardt/AP)

Cruz has emerged as the main challenger to Trump in Iowa. At an evening rally, Cruz offered to face Trump in a one-on-one debate anytime. He said Trump was scared of Kelly, telling supporters that skipping the debate was like refusing a job interview.

"If someone did that, didn't show up at the interview, you know what you'd say? You're fired," Cruz said, riffing on Trump's famous rejoinder from his reality TV show "The Apprentice."

At the very least, the high-profile debate feud serves as a major distraction in the Republican contest just six days before Iowa voters cast the first votes in the 2016 primary contest.

Falwell backs Trump

Trump has proven to be a master of commanding media attention at key moments. Among other things, he has previously called for a temporary ban on all Muslim immigrants and later questioned Cruz's presidential eligibility given that he was born in Canada.

Meanwhile, a week after heaping praise on him before a speech at Liberty University, the school's president Jerry Falwell Jr. is officially throwing his support behind Trump.

Falwell Jr. praised Trump in an introduction at the school last week, comparing Trump to his late father.

The campaign already had been using Falwell's remarks in a radio ad.

Family Research Council President Tony Perkins, for his part, said Tuesday he's personally endorsing Sen. Ted Cruz for president.

The leader of the conservative advocacy group announced his support for Cruz on the Fox network, saying he supported Cruz when he ran for the Senate and that he's confident the Texan governs "based on conservative principles."