US 2012: Rick Santorum Heads Pack for Minnesota

Unlikely candidate Rick Santorum has emerged as the shock favourite to win Minnesota ahead of runaway frontrunner Mitt Romney. Former governor Romney was leading the Colorado causus by a comfortable margin, however, and was likely to increase his delegate count ahead of Super Tuesday on 6 March.

Despite his big back-to-back victories in Florida and Nevada, Romney's three opponents, including former senator Santorum, have vowed to stay in the fight against increasing odds that they can overcome Romney's powerful campaign organisation and a massive financial advantage.

Santorum told Fox News: "This race is a long way from over."

Newt Gingrich, who until recently was joint frontrunner for the GOP nomination with Romney, has had a terrible week on the campaign trail.

He is in third position in both caucuses and has decided to head straight to Ohio - one of the key states to be contested on Super Tuesday

The former speaker of the House of Representatives, has been thrashed by near-unprecedented negative television advertising from Romney supporters. Gingrich promised, nevertheless, to battle on to the party's national nominating convention in August.

He said his goal was to "find a series of victories which by the end of the Texas primary will leave us at parity" with Romney by early April.

Texas congressman Ron Paul has already said that despite his unrealistic campaign bid he would continue to the national convention.