US presidential rivals Mitt Romney and Newt Gingrich battled to win last-minute supporters today in a South Carolina primary that could reshape the Republican nominating contest.
Mr Romney, the former governor of Massachusetts, must win the conservative southern state to preserve his front-runner status in the race to determine the Republican Party's challenger to president Barack Obama, a Democrat, in the November 6th election.
Mr Gingrich's recent rise in popularity has slowed Mr Romney's momentum.
A victory by the former speaker of the House of Representatives could prolong the state-by-state Republican nominating battle and give Mr Obama's re-election campaign a boost as his would-be Republican opponents beat each other up.
South Carolina is the third contest in the Republican nomination battle.
Former US senator Rick Santorum was the winner in Iowa on January 3rd and Mr Romney won in New Hampshire on January10th, with Mr Gingrich faring poorly in both those states.Polling in South Carolina closes at 7pm tonight.
Mr Romney, slipping in recent polls after coming under intense criticism from Mr Gingrich and other rivals, seemed to acknowledge he might not lock up the nomination this weekend.
"We've got a long way to go. So come join us in Florida, in Nevada, Michigan, Colorado," he said, standing on a chair in a crowded restaurant, Tommy's Country Ham House, and referring to Mr Gingrich as a "Washington insider.
"The next contest after South Carolina is the Florida primary on January 31st.
Mr Gingrich, a southern conservative who has called Mr Romney a Massachusetts moderate, showed up at the same restaurant shortly after Mr Romney left. "Where's Mitt?" he taunted.
"I don't think they have New England clam chowder on the menu." Clam chowder is popular in Massachusetts.
A new poll conducted by the American Research Group showed Mr Gingrich leading Mr Romney 40 per cent to 26 per cent among likely voters in South Carolina. The margin of error in the survey, conducted Thursday and Friday, was 4 percentage points.
Mr Romney may be helped if the South Carolina conservative vote is splintered among Gingrich, Santorum and US congressman Ron Paul, who is known for his libertarian views.
Voter turnout, which weather could influence, will also be key. A tornado watch was in effect for much of the state and severe thunderstorms were on the forecast.
Mr Gingrich's latest surge in opinion polls has created a different kind of storm. If he wins the state, it would mean that three different candidates will have won the first three Republican presidential nomination contests.
With strong debate performances, the thrice-married Mr Gingrich has fended off publicity about his turbulent marital history and painted himself as the more conservative candidate with experience as a reformer.
On Thursday, he rejected his second wife's accusation that he had asked her for an "open marriage" while he was having an affair with another woman in the 1990s.