As the battle for the labor vote between Hillary Clinton and Barack Obama is heating up in the crucial March 4 primary battleground of Ohio, Clinton leveled new charges on Saturday of unfair attacks by her Democratic presidential opponent.

Clinton's claims are based on two Obama campaign mailers, one targeting Clinton's advocacy for the North American Free Trade Agreement and the other attacking her on her health care stance. Both issues could be a source of vulnerability for Clinton in Ohio, which has a heavy labor vote.

Clinton -- now trailing Obama in the crucial delegate count -- needs wins in the delegate-rich states of Ohio and Texas to stay in the race.

"Enough with the speeches and the big rallies and then using tactics that are right out of Karl Rove's play book. This is wrong and every Democrat should be outraged," Clinton told reporters Saturday after a campaign rally in Cincinnati, Ohio.

"So shame on you Barack Obama. It is time you ran a campaign consistent with your messages in public. That's what I expect from you. Meet me in Ohio and let's have a debate about your tactics and your behavior in this campaign," Clinton said. The two are set for a debate Tuesday in Cleveland.

Obama, speaking later in the day to reporters in Columbus, Ohio, dismissed the accusations.

"I'm puzzled by the sudden change in tone unless these were just brought to her attention. It makes me think that there was something tactical about her getting so exercised this morning," Obama said.

By then, Obama's campaign already had responded with a statement standing by both pieces of campaign literature.

"Everything in those mailers is completely accurate, unlike the discredited attacks from Hillary Clinton's negative campaign that have been rejected in South Carolina, Wisconsin and across America," Obama campaign spokesman Bill Burton said in a prepared release.

NAFTA at Issue

Otherwise known as NAFTA, the agreement aimed at encouraging more trade among Mexico, the United States and Canada was signed early in Bill Clinton's presidency but since has become a major point of criticism by labor groups concerned with the loss of U.S. jobs to foreign competitors.

One of the mailers Obama sent shows a locked fence gate, with a "Closed" sign over what ostensibly is a factory. The mailer says: "Hillary Clinton believed NAFTA was a 'boon' to our economy. See inside ..."

Visibly angered, Clinton waved a copy of the mailers at the Cincinnati press conference, saying one of her supporters had just given them to her. The mailers have been in circulation for several days.

"I have to express my deep disappointment that he is continuing to send false and discredited mailings with information that is not true to the voters of Ohio. He says one thing in speeches, and then he turns around and does this," she told reporters.

She noted that the source of the quote where the word "boon" was cited -- New York Newsday -- has since clarified its use of that word. The newspaper said it accidentally attributed that word to Clinton when it should have made clear that it was the newspaper's language.

"I have been critical of NAFTA for years," Clinton said. "I have said repeatedly that it did not realize its potential or its promises and we had to change it."

"I don't believe that it is fair for this mailing to make claims that are not true," she continued, calling on Obama to retract the message and "take down these mailings."

On a blog entry dated Feb. 14, Newsday aimed at sorting out the record over the "boon" remarks, which first were published in the paper during Clinton's 2006 Senate re-election campaign. Newsday said the word appeared in a chart comparing her to her primary opponent.

According to Newsday: "In it [the chart], we did not have the Clinton campaign using the word 'boon' in describing NAFTA. The word was our characterization of how we best understood her position on NAFTA, based on a review of past stories and her public statements. ...

"We do not have a direct quote indicating her campaign told us she thought it was good for the economy at that time," Newsday continued; however, it noted: "Clinton's campaign did not contact us to question the item after it appeared in print."

The blog entry also addresses Obama's campaign's use of the disputed language: "Obama's use of the citation in this way does strike us as misleading. The quote marks make it look as if Hillary said 'boon,' not us. It's an example of the kind of slim reeds campaigns use to try to win an office."

Nevertheless, in the Obama campaign statement sent Saturday, a link points to that same blog entry under the headline: "Newsday Reviewed Clinton's Statements, Concluded She Supported NAFTA."

But Obama, at the Columbus news conference, granted some room for error.

Asked about the campaign's claims, despite Newsday's correction, Obama said: "Well, that's fair enough. It is true that the mailer went out before the newspaper amde thecorrection, right? That's my understanding, and I will need to check with staff on that.

"But the characterization that she supports NAFTA I think is indisputable."

Health Care Spat

The second mailing criticizes Clinton's stance on health care, an issue on which Clinton has staked her candidacy.

Obama's mailer says, "Hillary's health care plan forces everyone to buy insurance, even if you can't afford it ... and you pay a penalty if you don't."

Clinton, alluding to the 1993 "Harry and Louise" ads credited for sinking her universal health care plan, on Saturday said: "This health care mailing, which is very reminiscent of the health insurance industry attacks on the last time we tried to go after universal health care, is the worst kind of politics.

"Number one, it is wrong and untrue. Number two, it is exactly the talking points that the health insurance industry and the Republicans use on a daily basis.

"Sen. Obama knows that it is not true that my plan forces people to buy insurance even if they cannot afford it. My plan has more financial help."

Clinton's advisers repeatedly have criticized the Obama campaign's health care mailing on her plan, which requires everyone to be covered but offers tax credits and other subsidies to make insurance more affordable.

Obama's plan does not include the so-called "individual mandate" for adults, and he has argued that people cannot be required to buy coverage if they can't afford it. He has said his first priority is bringing down costs.

The Illinois senator's plan does include a mandate requiring parents to buy health insurance to cover children.

Clinton has said that she would consider garnishing wages for those who don't buy health insurance under her plan, but she said that is part of her current plan.

Nevertheless, Obama spokesman Burton said, "She herself has said that under the Clinton health care plan, she would consider going after the wages of Americans who don't purchase health insurance, whether they can afford it or not."

Obama followed later by saying: "There's nothing in there that's factually inaccurate."

Clinton also pushed back Saturday on questions about how her campaign had burned through nearly $130 million, only to be vastly outspent by Obama on ads and organization in several key states.

She also denied having overspent on campaign consultants. Financial reports published this week showed she had paid $7.5 million to the consulting firm of her senior strategist Mark Penn for polling and direct mail services. Clinton's top media adviser, Mandy Grunwald, was paid more than $2 million to produce ads.

"Our money goes to directly communicating with voters. That's where the money goes," Clinton said.

She added that she felt good about her prospects in Ohio and Texas but refused to say whether she needed to win both states to stay in the race.

"Let's let the people of Ohio vote. Let's actually have an election and then we can look at the results," she said.

Click here to read the Obama campaign NAFTA mailer, posted on The Cleveland Plain Dealer's Web site.

Click here to read the Newsday blog regarding the "boon" comment.

Click here to read the Obama campaign health care mailer.

FOX News' Steve Brown, Aaron Bruns, Bonney Kapp and Major Garrett and The Associated Press contributed to this report.