US:Republican presidential frontrunner Rudy Giuliani has condemned as a "hit job" revelations that, as New York mayor, he billed obscure city agencies for his security detail's travel expenses during secret visits to the Hamptons with Judith Nathan, now his third wife.
"This was really done to try to focus on my personal life," Mr Giuliani said, adding that all the expenses were legitimate and no public funds were misused.
Official documents show police officers' stays at hotels billed to the New York City Loft Board, the office for People with Disabilities, and other agencies.
Mr Giuliani said the New York Police Department always reimbursed the agencies for the expenses. "They were handled openly, honestly, it was the practice that was going on since my first term and the idea was to get the bills paid quickly," he said.
New York City Comptroller Bill Thompson described Mr Giuliani's billing methods as a "very convoluted" way of getting things done. "That's not the way that we operate these days, and it would not be the preferred way of doing business," he said.
Although Mr Giuliani has described the expenses story as false, he has not disputed any of the facts first reported by the Politico newspaper this week.
Critics have suggested that the cumbersome billing system may have been designed to conceal Mr Giuliani's visits to his then-secret girlfriend, and the story has cast an unwelcome spotlight on the former mayor's private life, which has been a cause of concern to some conservative Christians.
It comes as the Republican presidential race has taken a negative turn, with two attack adverts against former Massachusetts governor Mitt Romney set to be broadcast in New Hampshire this weekend.
An independent group has launched a television advert accusing Mr Romney of flip-flopping on abortion, and a Republican gay rights group has paid for a radio advert claiming that the former governor has also shifted positions on tax policy.
The Log Cabin Republicans, a gay group within the party, is unofficially backing Mr Giuliani, who has a liberal record on gay rights. Members of the group say, however, that they have agreed not to endorse Mr Giuliani officially in case their support will alienate Christian conservatives.
Mr Romney is leading in the early-voting states of Iowa and New Hampshire, although he trails far behind Mr Giuliani in national polls.