Donald Trumps autographs copies of his new book at Trump Tower in New York on Tuesday. (Richard Drew/AP)

NEW YORK — As Marco Rubio has slowly gained traction in early polls, especially after his well-received debate performance last week, Donald Trump has ratcheted up his criticism of the senator from Florida. On Tuesday, Trump called Rubio "overrated" and raised questions about the senator's personal finances.

"All you have to do is look at his credit card — I mean, he's a disaster with his credit cards," Trump said during a news conference on Tuesday morning at Trump Tower. "For years I've been hearing that his credit cards are a disaster.... He certainly lives above his means, there's no question about that."

Rubio made $174,000 as a U.S. senator last year, in addition to more than $50,000 in book royalties, a university teaching position and a rental property. Yet, that same year, he cashed out nearly $70,000 in retirement funds. Rubio, 44, the son of a bartender and a maid, has defended himself against accusations that he is reckless with money, saying that he had to take out loans to pay for school and is now raising a young family.

[Does Rubio have a spending problem?]

Trump's comments came as he promoted his latest book, "Crippled America: How to Make America Great Again," which includes documentation of his multibillion-dollar net worth and a list of the dozens of luxury resorts and other properties he owns. Although Trump, 69, has never held elected office, he has said that his financial success in the business world has prepared him for the White House.

That wasn't Trump's only line of attack against Rubio on Tuesday. He also said that the senator was "overrated," weak on immigration and has missed too many Senate votes. Trump said former Florida governor Jeb Bush was right to criticize Rubio's voting record during last week's Republican debate.

"Bush gave a very weak message, I agree with that," Trump said. "It was poorly delivered, but the facts are on Bush's side, and, ultimately, I think Marco's going to be hurt very badly."

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