Newt Gingrich wins South Carolina primary

Republican presidential candidate Newt Gingrich beat frontrunner Mitt Romney in South Carolina in a victory that indicates the party's battle to pick a challenger to President Barack Obama may last months, not weeks.

Mr Gingrich's triumph in the conservative southern state injects unexpected volatility into the Republican nominating race.

Instead, voters in South Carolina rejected Mr Romney's pitch that he is the best bet to fix a broken US economy and defeat Mr Obama in the election on 6 November.

Three different candidates - Mr Gingrich, Mr Romney and former US senator Rick Santorum - have won the first three contests in the state-by-state battle for the Republican presidential nomination to face Mr Obama.

Mr Gingrich received 40% of the vote, followed by Mr Romney with 28%.

Mr Santorum was in third with 17% and US congressman Ron Paul was in fourth with 13%.

The next contest is the Florida primary on 31 January.

Mr Gingrich contrasted his sometimes-chaotic management style with Mr Romney's buttoned-down approach, arguing that his campaign was powered by ideas rather than logistics.

Mr Romney is one of the wealthiest candidates ever to run for president and his campaign is well financed.

"We don't have the kind of money that at least one of the candidates have. But we do have ideas and we do have people," Mr Gingrich told supporters.

Mr Romney acknowledged that there will be a long primary season.

He said he would continue to run on his business record and paint Mr Gingrich as a creature of Washington in the weeks ahead.

"I don't shrink from competition, I embrace it," he told supporters. "I believe competition makes us all better. I know it's making our campaign stronger."

The winner of South Carolina's Republican presidential primary has gone on to win the party's nomination in every presidential election since 1980.

Romney to release tax returns

Mr Romney said today that he will release tax returns for the last two years after he came under attack from rivals for delaying his financial disclosures.

He said: "I will release my tax returns for 2010, which is the last returns which were completed, on Tuesday of this week.

"I will also release at the same time an estimate for 2011 tax returns.

"We made a mistake holding off as long as we did and it just was a distraction.

"I know people will try and find something, but we pay full fair taxes and I'm sure people will find it's a substantial amount."