Manchester – As Hillary Clinton steps up her attacks on Democratic rival Barack Obama in first-caucus state Iowa, her campaign is alleging "dirty tricks" by Obama's campaign in New Hampshire.

"Dirty tricks" is a familiar term in political campaigns, especially in the latter stages as races tighten and campaign officials become increasingly intense.

With the Iowa caucus on Jan. 3 and the New Hampshire primary on Jan. 8, Clinton last weekend saw Obama overtake her long-held lead in Iowa in a Des Moines Register poll. She maintains a significant lead in New Hampshire, but on Sunday began ramping up her criticism of Obama in the first-caucus state. According to news reports, she contended his positions on health care and the handling of campaign finance rules have begun to reflect on his character. Her campaign mocked Obama for saying that he wrote an essay in kindergarten entitled, "I Want to be President," and then yesterday, Clinton strategist Mark Penn said the criticism was actually a joke.

Clinton said on Sunday that after "months on the receiving (end) of consistent attacks," she would return fire, adding, "Now the fun part starts." She is scheduled to return to New Hampshire tomorrow.

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Her national campaign manager, Patti Solis Doyle, charged on Monday night in an e-mail to Iowa and New Hampshire supporters that the campaign has been told by other Clinton supporters "Obama staffers are berating Hillary supporters on the phone with negative attacks against her." The e-mail subject was: "The dirty tricks are starting."

Also yesterday, a North Country Clinton supporter accused a John Edwards campaign worker of calling her last Friday, during the height of the tense hostage situation in Rochester, and trying to convince her to vote for Edwards.

Edwards' campaign spokesman responded by accusing the Clinton campaign of using "Friday's frightening situation to attack other campaigns."

Obama spokesman Bill Burton, in his own e-mail to Obama supporters, called Doyle's allegations a "flat-out falsehood" and "the latest attack in a silly season where our opponents have promised to stop at nothing in an effort to tarnish Barack Obama's character."

Obama's camp on Monday urged supporters to contribute $25 to "show our opponents that this kind of negativity will only make us stronger in our determination to bring about the change America needs."

Doyle's e-mail does not give any sources for the alleged negative calls by Obama staffers. Clinton state campaign spokesman Kathleen Strand provided the New Hampshire Union Leader with two New Hampshire names, Barbara Therriault of Plymouth and Tiffany Downing of Somersworth.

Downing could not be reached, but Therriault, owner of the Thomas Roberts salon, said that last week she received a call from "a gentleman who identified himself as an Obama campaign worker."

She said that when he told the worker she was a Clinton supporter, he asked why she supporter her.

"I cited women's rights and health care, he said that on health care, she didn't do anything as first lady, so what made me think she would do something now. He said when South Dakota tried to outlaw abortions, she would not help but Obama went there and made phone calls."

Therriault said the caller "became more aggressive and argumentative" as the call continued. "I told him I didn't appreciate his aggressive tone and hung up."

Therriault said she believed the caller was reading from campaign "talking points because every time I could think of a reason why I was supporting Hillary, he came back with a pat and aggressive answer with specifics."

Obama campaign spokesman Reid Cherlin countered with a Dover woman who backs Obama. Jennifer Steifels said that last week she was "put on guard" by a self-identified Clinton caller.

Steifels said that when she told the caller she backed Obama, "She said, 'Are you aware that his health care plan doesn't cover everyone?'" She said the caller then asked her to look at the Clinton campaign Web site.

"I was sort of taken aback," she said.

Strand also targeted John Edwards' campaign, forwarding an e-mail from Roxana Forsyth of West Stewartstown, who then told the Union Leader by telephone that she received a call from a young, "chipper" Edwards volunteer at shortly after 4 p.m. last Friday, while Leeland Eisenberg allegedly held Clinton campaign volunteers hostage in the Rochester campaign office. She said the caller continued to try to convince her to support Edwards even after she told him that she thought it was rude that he was making such calls during the hostage crisis.

"He kind of chuckled and wouldn't let up. I hung up on him," Forsyth said. She said she had been "on the fence," but now supports Clinton. She said she informed the Clinton campaign of the call "just to let them know about it."

Edwards spokesman Kate Bedingfield responded, "It is deeply disappointing that the Clinton campaign is choosing to use Friday's frightening situation to attack other campaigns."

She said that during the hostage situation, "all of our campaigns were united in concern and hope for the staffers and volunteers in Rochester and it is disappointing to see the Clinton team trying to take political advantage of a frightening situation."