Republican presidential candidate Donald Trump speaks during a news conference at Trump Tower, in New York (AP Photo/Richard Drew)

Republican presidential candidate Donald Trump is finally putting some money on the line as several of his rivals receive new attention and support.

The billionaire businessman, who has so far relied on the news media to promote his unorthodox campaign, says in an interview airing Tuesday night on Fox News that his campaign will begin paid advertising soon in the first states to vote in the GOP nomination race.

"We're going to start some ads over the next, I think, two days," he said, according to an early transcript from Fox News Channel's "Hannity." ''Certainly in Iowa, we're going to start ads and in New Hampshire, and I think in South Carolina too. So, we're going to start advertising a little bit."

Trump's campaign did not immediately respond to a request for more details about the timing or how much Trump planned to spend. Trump's campaign had not reserved any television advertising time as of Tuesday, according to Kantar Media's CMAG advertising tracker.

Trump said in early October that he had ads in the works, but in the weeks since has said he didn't think they were necessary, airing concerns about potential Trump overload.

Despite Trump's boasting that he self-funds his campaign, the vast majority of the cash he has spent so far has come from donor contributions. Still, he has spent far less than many of his rivals - thanks, he's said, to the fact that he hasn't had to spend millions on paid ads.

"So far, I was going to have spent 25 million by this time, I've spent nothing," he said, according to the transcript. "But we are going to start spending a little bit of money over the next three or four weeks."

Trump dominated opinion surveys throughout the summer, but several of his rivals have been garnering new attention from voters and donors this fall.

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