CLEVELAND, Ohio (CNN) -- Democrats Hillary Clinton and Barack Obama sparred with each other over negative campaigning, health care and free trade Tuesday, a week before key primaries in Texas and Ohio.
Sens. Hillary Clinton and Barack Obama faced off Tuesday in the final debate before the March 4 primaries.
Those contests are must-wins for Clinton if she is to continue to contest Obama for the nomination, as even former President Clinton suggests.
Debating at Cleveland State University, Clinton repeated angry claims from the campaign trail that Obama mischaracterized her stances on health care and NAFTA in political material mailed to voters in Ohio.
"I have a great deal of respect for Sen. Obama, but we have differences," she said. "In the last several days, some of those differences in tactics and choices that Sen. Obama's campaign has made regarding fliers and mailers and other information that has been put out ... have been very disturbing to me."
The mailers, which Obama defends, claim that Clinton's health care plan would force people who don't want insurance to buy it. They also say she has been inconsistent on NAFTA, which many in industrial states like Ohio blame for shipping blue-collar jobs overseas. Watch the candidates' exchange over health care »
Clinton said her health plan would cover everyone and would be affordable to everyone.
While she has made multiple statements saying NAFTA has helped the economy in some parts of the United States, Clinton said she has always maintained that it needs to be improved to provide better labor and environmental protections in Mexico and Canada. If that happened, she said, fewer American jobs would go overseas.
She blasted the health care mailing in particular, saying it's "almost as if the health insurance companies and the Republicans wrote it." Watch analysts break down the debate performances »
Obama said the mailings are common practice in political campaigns and raise valid differences between his stances and Clinton's. He said he, too, has been targeted by negative Clinton advertisements.
"Sen. Clinton has consistently sent out negative attacks on us," he said. "We haven't whined about it because I understand that's the nature of these campaigns.
"But to suggest that our mailer is somehow different to the kind of approach Sen Clinton has taken throughout this campaign certainly is not accurate."
With Obama having won 11 statewide contests in a row and a recent set of national polling suggesting he has the support of 50 percent of Democrats to her 40 percent, Clinton has sharpened her attacks on Obama in the past week.
According to CNN estimates, Obama leads Clinton in the delegate race, 1,360 to 1,269. In all, 2,025 delegates are needed to seal the Democratic nomination.
Even Clinton's husband, former President Bill Clinton, has suggested that if she does not win in Ohio and Texas, her campaign will face a dramatically difficult challenge keeping up with the surging Obama. Rhode Island and Vermont also hold primaries on March 4.
Clinton denied knowledge of a photograph of Obama wearing Somali tribal garb that was provided to the Drudge Report Web site Monday. Matt Drudge wrote that the photo was leaked to him by the Clinton campaign in what Obama called an effort to reinforce false notions that he is either foreign-born or a Muslim.
The picture was taken during a 2006 visit to Africa by the senator. It is common for political leaders to be given gifts and asked to wear traditional garb on such trips.
Clinton denied any knowledge of the photo coming from one of her staff.
"So far as I know, it did not," she said. "That's not the kind of behavior that I condone or expect from the people working in my campaign."
Obama, a senator from Illinois, said he believes her.
"I take Sen. Clinton at her word that she knows nothing about the photo," he said.
As in many of their debates, health care was a prime focus, with the first 16 minutes of the debate devoted to it. The two staked out familiar themes -- Clinton saying her plan would guarantee health coverage for all Americans and Obama touting a plan he says would make it affordable for everyone but not require them to buy it if they don't want it.
Responding to a question on NAFTA in which moderator Tim Russert listed comments he said show Clinton once supported the free-trade agreement, the New York senator appeared to lash out at media bias against her -- a claim members of her campaign have made repeatedly -- and in favor of Obama.
"I just find it kind of curious that I keep getting the first question on all of these issues," she said before adding, in reference to a "Saturday Night Live" skit, "Maybe we should ask Barack if he's comfortable and needs another pillow." E-mail to a friend