HILLARY Clinton has been branded a "monster" by one of Barack Obama's top advisers, as the gloves come off in the race to win the Democrat nomination.
In an unguarded moment during an interview with The Scotsman in London, Samantha Power, Mr Obama's key foreign policy aide, let slip the camp's true feelings about the former first lady.
Her comments came as Mr Obama, whose defeats in Texas and Ohio on Tuesday were largely attributed to a series of negative attacks on him, vowed to turn up the heat on Mrs Clinton over her claims to be the more experienced candidate.
Yesterday, the Obama camp went on the offensive, pointing out that Mrs Clinton has still not released her tax return and casting doubt on her experience.
In response, a Clinton adviser said the attack reminded him of the witch-hunt led by special prosecutor Kenneth Starr, which led to the impeachment of her husband, Bill, when he was president.
Earlier, clearly rattled by the Ohio defeat, Ms Power told The Scotsman Mrs Clinton was stopping at nothing to try to seize the lead from her candidate.
"We f***** up in Ohio," she admitted. "In Ohio, they are obsessed and Hillary is going to town on it, because she knows Ohio's the only place they can win.
"She is a monster, too – that is off the record – she is stooping to anything," Ms Power said, hastily trying to withdraw her remark.
Ms Power said of the Clinton campaign: "Here, it looks like desperation. I hope it looks like desperation there, too.
"You just look at her and think, 'Ergh'. But if you are poor and she is telling you some story about how Obama is going to take your job away, maybe it will be more effective. The amount of deceit she has put forward is really unattractive."
Ms Power's comments reveal how the inexperienced Obama campaign is coming under increasing pressure from a battle-hardened Clinton camp that saw Ohio as its last chance to save its candidate.
Before Tuesday's vote in Ohio, the press and the Clinton camp seized on remarks by Austan Goolsbee, Ms Power's colleague, on the North America Free Trade Agreement (Nafta). His comments are widely believed to have cost Mr Obama the Ohio Democratic presidential primary.
Mr Goolsbee, Mr Obama's top economic policy adviser, had told Canadian officials a public pledge to force a renegotiation of Nafta with tougher labour and environmental rules was "more about political positioning".
But the Clinton camp said Mr Obama could not tell the public of Ohio, where many manufacturing jobs have been lost, one thing and then tell a foreign government something else behind closed doors.
Yesterday, Mr Obama blamed fierce attacks by Mrs Clinton for his defeats in this week's big primaries, and quickly made good on a promise to sharpen his criticism of her, in what promises to become an all-out brawl in the race for the White House.
The Illinois senator took the offensive against Mrs Clinton, targeting her claims she is more experienced in handling foreign policy. "Was she negotiating treaties? Was she handling crises? The answer is no," he said. "She made a series of arguments on why she should be a superior candidate. It's important to examine that argument."
In recent days, the former first lady argued that Mr Obama was getting a free ride with the media and had hinted he was not ready to be commander-in-chief in a crisis.
Mrs Clinton, asked about her national security qualifications, highlighted a series of events in which she played a role, including peace talks in Northern Ireland, the Kosovo refugee crisis and standing up for women's rights in China.
Mr Obama's aides went on the offensive yesterday, holding a conference call to ask why Mrs Clinton had not released her tax returns. Her campaign team responded with a statement e-mailed to reporters while they were on the call that said the Clintons' returns since they left the White House would be made public around 15 April.
"There's no doubt Senator Clinton went very negative over the last week," Mr Obama said, adding that the Clinton campaign's attacks "had some impact" on the poll results, "particularly in the context where many of you in the press had been persuaded you had been too hard on her and too soft on me".
After this latest row, Howard Dean, head of the Democratic Party, warned that the tone of the campaign "may get nastier" and said discussions would take place to try to prevent that.
After Mr Obama's camp had raised the issue of Mrs Clinton's failure to release her tax returns, Howard Wolfson, a spokesman for Mrs Clinton, described the statement as being reminiscent of the attacks the Clintons endured during investigations by prosecutor Kenneth Starr in the 1990s, which many saw as politically motivated.
Mr Wolfson's introduction of Mr Starr's name again portrays Mrs Clinton as a victim, while her attacks on Mr Obama's "preparedness to be commander in chief and steward of the economy" continue.
Mr Wolfson said: "I, for one, do not believe imitating Ken Starr is the way to win a Democratic primary election for president."
The Clinton campaign has also attacked Mr Obama's inexperience on foreign matters, but Ms Power insisted he was not afraid to take tough decisions on this front.
She added: "Hillary Clinton always portrays his position on meeting with dictators as naive."
Ms Power also described working for Mr Obama as a pleasure, and said that people who knew him "adore him".
She added: "When we started this, we were all backing the guy who was supposed to lose.
"He was 25 points down going in to Iowa in January.
"If people were in this for the job or the political reward they would have gone somewhere else. They would not have gone to Barack."
Ms Power also said she believed Gordon Brown and Mr Obama would get on "like a house on fire".
Ms Power was in the UK to promote her book on Sergio Vieira de Mello, the extraordinary UN representative who died in a Baghdad bomb attack.
PUBLISH AND BE DAMNED
WHEN is off the record actually off the record? When the rules are established in advance.
Journalists are always looking for knowledge and want the information they receive to be available for publication.
But occasionally an interviewer will accept an exchange is "off the record" and that the conversation is not attributable. Remarks can be used as background to inform a journalist's article.
If a conversation is to be off the record, that agreement is usually thrashed out before the interview begins. Sometimes, public figures say something and then attempt to retract it by insisting it was "off the record" after the event.
But by then it is too late, particularly if it is in the public interest that the story be published.
In this instance, Samantha Power was promoting her book and it was established in advance that the interview was on the record.
A WOMAN OF POWER
SAMANTHA Power is the embodiment of the American immigrant dream.
Born in Dublin in 1970, she moved to the United States with her mother aged nine.
After being educated in state schools in Pittsburgh and Georgia, she gained entry to the prestigious Yale University, where she studied history. The self-deprecating Ms Power said this changed her life and opened many doors.
She worked as freelance journalist in Bosnia, after teaching herself the language in Croatia. Her only other journalism experience prior to that was covering the Yale women's volleyball team.
After graduating from Harvard Law School, she became an executive director and founder of the Carr Centre for Human Rights Policy at Harvard.
The 37-year-old already has one Pulitzer Prize behind her, for her book A Problem from Hell: America and the Age of Genocide and she is in the UK and Ireland to plug her new book, Chasing the Flame: Sergio Vieira de Mello and the Fight to Save the World.
Ms Power was head-hunted by Barack Obama to become his foreign-policy adviser in 2005 and combines this role with her job as a Time magazine columnist and professor of practice of global leadership and public policy at Harvard.