Newt Gingrich, a US Republican presidential contender, has strongly criticised the US media at a presidential debate in South Carolina and strenuously denied an allegation that he asked his second wife to tolerate an "open marriage".
Thursday's event was the final chance for rivals to reduce front-runner Mitt Romney's South Carolina lead in the context of a debate.
"I'm appalled that you would begin a presidential debate on a topic like that," Gingrich told CNN's debate moderator.
Gingrich, a former speaker of the US House of Representatives, is rising in the polls in the run-up to Saturday's primary vote in South Carolina in which he is campaigning as the conservative alternative to Romney.
The former congressman has made the media's coverage a frequent target during the 2012 campaign.
Gingrich came under attack frequently in the debate of almost two hours and deftly defended himself with the kind of
strong debate performance that has buoyed his up-and-down campaign all year.
However, the fact that character issues were aired publicly, as well as sharp questions about his 1990s tenure as House speaker, could damage Gingrich's hopes.
In a move designed to embarrass Romney, Gingrich released his most recent tax returns, a reminder that the multi-millionaire Romney still had not produced his own. Romney pledged to do so in April.
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"I'm not going to apologise for being successful," Romney said.
Romney will take a big step towards claiming the Republican nomination if he wins on Saturday after his New Hampshire win on January 10 and his near-victory in Iowa on January 3.
Romney's rivals had him in their sights to try to deny him victory, expressing doubts about his conservative convictions.
The CNN-sponsored debate got off to an unpredictable start when John King, the moderator, asked Gingrich to respond to charges put forth by his ex-wife Marianne that he had sought an "open marriage" while having an affair.
"I think the disruptive, vicious, negative nature of the news media makes it harder to govern this country," Gingrich said.
Patty Culhane, Al Jazeera's correspondent reporting from South Carolina, said "Gingrich received a huge round of applause" following his attack on the media.
"The crowd seemed to like it," she said.
A new Reuters/Ipsos poll conducted of 656 likely South Carolina voters showed Romney with 35 per cent support, Gingrich with 23 per cent support, and former Senator Rick Santorum with 15 per cent support.