Fredreka Schouten

USA TODAY

WASHINGTON — Republican Donald Trump said he is donating $10 million to his presidential campaign Friday, as he faced fresh questions about claims that he's invested $100 million of his fortune in the White House bid.

The New York real-estate magnate announced the donation on Fox News in a Friday morning interview but would not say whether he would hit the $100 million target, a figure he routinely touts at rallies and interviews. “We’ll see what’s needed,” he said.

He also touted the donation in a fundraising email to supporters later in the day. “I want to say thanks to all of our supporters by putting in an unprecedented TEN MILLION DOLLARS to this campaign,” he said.

The Wall Street Journal, citing unnamed campaign aides, said the money will go to advertising in key battlegrounds.

It’s not clear how far the $10 million infusion — or even larger sums — can take Trump in the final sprint to Election Day, given the already crowded airwaves in states such as Florida and Nevada.

“There’s a big difference between $10 million in August and $10 million in the last 10 days of the campaign,” said Steven Passwaiter, who tracks political advertising as vice president of Kantar Media/CMAG. “He’s going to be paying the highest rates of the season.”

Federal Election Commission reports filed late Thursday night showed Trump scaling back his giving dramatically during the first three weeks of October, donating just shy of $31,000 to his campaign for rent and salaries – well short of the $2 million he typically has contributed on a monthly basis during the general-election campaign.

In all, he had donated $56.1 million through Oct. 19, even as Democrat Hillary Clinton and her allies entered the homestretch with an enormous financial advantage over the Republican nominee.

Trump’s plan to donate $10 million still leaves him $34 million shy of the target.

Donald Trump hasn't invested $100 million in White House race - yet

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Other wealthy Republicans also appeared to turn off the spigot to pro-Trump super PACs in October as he slipped in the polls.

One, Rebuilding America Now, raised nearly $215,000 during the first three weeks of October, after collecting nearly $18 million to assist Trump in the July-to-September fundraising quarter.

Billionaire investor Peter Thiel, whose plan to donate $1.25 million to help Trump sparked outrage among some of his Silicon Valley peers, gave just $250,000 last month to a joint fundraising committee Trump operates with the Republican National Committee, Federal Election Commission records show. That does not mean further Thiel donations will not show up in later filings by a super PAC backing Trump.

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The reports also show virtually no donations — just $25 — in October to another pro-Trump PAC controlled by hedge-fund billionaire Robert Mercer and his daughter Rebekah Mercer. Robert Mercer last donated to the group in July, when he provided $2 million in seed money. The group has lower expenses than many super PAC because it focuses on digital advertising targeting Clinton, rather than costly television commercials.

The Mercers declined comment through a spokeswoman.

Contributing: Christopher Schnaars