RENO - Republican White House frontrunner Mitt Romney was embroiled in a new gaffe Wednesday as he tried to roll back potentially damaging comments that he was not concerned about the very poor.

Fresh from his victory over rival former House speaker Newt Gingrich in Florida, Romney headed into the western battleground of Nevada with the race to be the Republican challenger in November elections widening into more states.

But the wealthy businessman, who last week acknowledged earning $20 million in 2010, ran straight into trouble when he said he was "not concerned about the very poor" but cared more about helping struggling middle-class Americans.

"I'm not concerned about the very poor. We have a safety net there. If it needs repair, I'll fix it. I'm not concerned about the very rich, they're doing just fine," the venture capitalist who lives off his investments told CNN.

"I'm concerned about the very heart of America, the 90-95 percent of Americans who right now are struggling and I'll continue to take that message across the nation."

The remarks will renew doubts about Romney's ability to connect with ordinary voters, struggling to make ends meet, with unemployment still around 8.6 percent as the US economy gropes its way out of the recession.

And they come amid a fierce debate in the United States about widening income disparities, ahead of the November vote in which Democratic President Barack Obama will seek re-election.

Romney swiftly tried to explain his remarks, telling reporters travelling with him on his plane: "You've got to take the whole sentence and then change it just a bit, it sounds very different.

"My focus, my concern, my energy will be devoted to helping... we have a safety net for the poor in the condition and if there are holes in it, I will work to repair that."

The former Massachusetts governor trounced Gingrich, his closest rival, by more than 14 percentage points in Florida.

Now as the first western state in the 2012 Republican nomination battle, Nevada thrusts new demographics and issues into the limelight, including concerns over illegal immigration, the environment and natural resources.

Like Florida, the "Silver State" has been badly hit by the recession with soaring unemployment and a real estate industry on its knees following the housing market meltdown.

But Romney, who won handily here in the 2008 White House race, will be boosted by the large Mormon population. Four years ago, some 26 percent of Nevada Republican caucusgoers were Mormon and 95 percent of them voted for Romney.

Nevada holds its caucus vote on Saturday, along with a similar caucus in Maine, while five other US states will hold votes in the coming month.

Gingrich, 68, had shocked the party establishment when he thumped Romney, 64, in South Carolina earlier this month, but he was defeated in the end by the millionaire businessman's deeper pockets and superior political organization.

In a sign of how bitter the campaign has become, Gingrich broke with tradition by neither congratulating Romney nor calling him after the vote.

"He didn't call last night," Romney told Fox News on Wednesday. "Speaker Gingrich, I guess, doesn't participate in that tradition."

Instead, Gingrich vowed to wage a long-haul battle all the way to the August 27-30 convention, which will formally crown the party's nominee.

"This will be a two-person race between the conservative leader, Newt Gingrich, and the Massachusetts moderate," he told supporters in Orlando, referring to Romney.

The former Georgia lawmaker was due to start campaigning here on Wednesday while Texas representative Ron Paul and Pennsylvania's former senator Rick Santorum have already been busy canvassing the state.

In Florida, Santorum scored a distant third place with 13.34 percent of the vote, while Paul was fourth with 7.01 percent.

Paul however is pinning his hopes on the caucus states, and refusing to surrender the race any time soon.

"I saw a statistic we're in third place when it comes to delegates. That's what really counts," he said, referring to the delegates awarded by each state to winning candidates who then select the nominee at the convention.

"And we've only gotten started! Now, the counting really occurs."