Republican White House hopeful Mitt Romney romped to victory in the Nevada caucuses, cementing his position as frontrunner to take on President Barack Obama in November.

But his main rival, former House speaker Newt Gingrich, who came in second place late Saturday, vowed to fight all the way to August for his party’s nomination, which he insists he can still win.

The results come as the candidates prepare for three more state polls this week, with experts predicting that Mr Romney and Mr Gingrich will likely duel right up to the party’s summer convention in Florida.

With 71 per cent of Nevada votes counted, Mr Romney had 48 per cent of the vote – a decisive lead, although below his 50 per cent in 2008 – followed by 23 per cent for Mr Gingrich.

Texas Representative Ron Paul was third with 18 per cent, followed by religious conservative Rick Santorum, a former US senator from Pennsylvania, with 11 per cent.

In his speech, Mr Romney failed to mention a single one of his Republican rivals, training his attacks solely on Mr Obama – in a clear sign that he wants to reassert his above-the-fray frontrunner status.

“This President’s misguided policies made these tough times last longer,” he said. “America needs a president who can fix the economy because he understands the economy, and I do, and I will.”

But Mr Gingrich vowed to fight on, saying that he hopes to draw equal with front runner Romney in delegate numbers by April – and blamed Mr Romney for rumours that he might withdraw.