Romney under fire in Republican debate

A tightened field vying for the Republican nomination took aim at frontrunner Mitt Romney in a fiery debate just days before South Carolina's presidential primary.

Before a raucous audience, the four candidates lagging behind Romney in polls ahead of Saturday's key vote sought, and largely failed, to land damaging blows on the former Massachusetts governor.

Ex-House speaker Newt Gingrich, who is trailing in the battle to be the party's standard-bearer in the November election against President Barack Obama, came out swinging.

Romney should answer questions about his time as a venture capitalist with a company called Bain Capital, Gingrich said, after Romney's rivals slammed him for buying out firms to leave them bankrupt and reap the rewards.

"There was a pattern in some companies, a handful of them, with leaving them with enormous debt, and then within a year or two or three having them go broke. I think that is something he ought to answer," Gingrich charged.

But Romney hit back against the attacks, led in a kind of pincer movement between Gingrich and former US senator Rick Santorum.

"My record as the governor of Massachusetts and as the person that led the Olympics flowed from the fact that I had experience turning around tough situations. That I worked in the private sector, demonstrated a record of success," Romney told the debate hosted by Fox News in Myrtle Beach.

He also pushed back at the prospect of Washington helping Europe deal with its crippling banking crisis.

"We don't need to run over to Europe to save their banking stem or to pump money into the banks in this country," Romney argued.

The field in the Republican race has narrowed dramatically to five ahead of Saturday's vote, after Jon Huntsman, the former US ambassador to China, bowed out earlier Monday.

The most moderate candidate in the race, Huntsman ended his struggling White House bid and called on Republicans to unite in support of Romney, who has already won the first two 2012 nominating contests in Iowa and New Hampshire.

With Romney seemingly on an unstoppable course to win the nomination, Huntsman had been running in last place in the polls ahead of the primary, as his centre positions failed to draw support of key conservative voters.

His departure left hardened social conservatives Santorum, Gingrich and Texas Governor Rick Perry, hoping the evangelical base in South Carolina will swing in their favour, along with Texas Representative Ron Paul.

Under pressure from Gingrich and Perry, Romney was called on to release his tax records, and said he may do later in the year, but resisted making a firm promise.

"I anticipate that most likely I am going to get asked to do that around the April time period," Romney said, referring to US tax day. "I'll keep that open."

Perry meanwhile in a foreign policy stumble, stood out in the debate for describing Turkey, a key US ally, as state "ruled by Islamic extremists."

Gingrich was meanwhile able to stir up support from the audience, who at one point gave him a standing ovation when pressed on his stance to boost child employment.

According to new CNN/ORC poll released Monday, frontrunner Romney and Democrat Obama are in a dead heat, with the Republican taking a slight 48-47 percent edge among registered voters, and Obama ahead among all respondents, 49-47 percent.