(CNN) – As support for Newt Gingrich surges in Iowa, Mitt Romney’s lead has dwindled in New Hampshire, according to new polls measuring support for candidates in the early caucus and primary states.
In a poll released Sunday, former House Speaker Gingrich has risen to the top in Iowa and former Massachusetts Gov. Romney remains ahead in New Hampshire, with competitors catching up.
The NBC News/Marist Poll indicates Gingrich has 26% support among likely Republican caucus-goers 30 days from the first GOP presidential nominating contest in January. Eighteen percent said they back Romney with Texas Rep. Ron Paul close behind at 17%.
The margin between Gingrich, Romney, and Paul falls within the sampling error for the survey.
Texas Gov. Rick Perry tied with businessman Herman Cain, who suspended his presidential campaign Saturday, at 9% each. Minnesota Rep. Michele Bachmann, who won the Ames Straw Poll in Iowa last August, tied with former Pennsylvania Sen. Rick Santorum at 5% support, followed by former Utah Gov. Jon Huntsman, who received 2% in the survey.
In October, Romney carried 26% support while Gingrich netted only 3%. Now that Cain has suspended his campaign activities, the poll shows likely GOP caucus-goers may shift their support to Gingrich, who was the second choice among Cain supporters. And Gingrich’s advantage over Romney widens among likely caucus-goers who describe themselves as conservative by a 34-to-20% margin.
Nine percent said they remain undecided in Iowa, and only four in 10 strongly support their choice of candidate.
In New Hampshire, Romney is still leading but is increasingly threatened by Gingrich, the poll found.
One month ago, Romney earned 45% support, with his closest opponents in the low teens. Now Romney's support has fallen to 39%, with Gingrich earning 23%.
However, Romney still comes out ahead when asked who voters think could defeat President Barack Obama in 2012. The poll found both Romney and Paul would be competitive in a hypothetical match-up against Obama, while Gingrich lags the president by 10 points in the match-up.
The poll also shows more voters are making up their minds about the candidate they will support. Forty-nine percent of likely Republican New Hampshire primary voters said they "strongly support" their pick.
Ron Paul and Jon Huntsman also drew support, at 16% and 9% respectively. Herman Cain, who only recently came in second in several state polls, earned only 2%. Michelle Bachmann and Rick Perry received 3%, and Rick Santorum 1%.
The NBC News/Marist Poll in Iowa was conducted by telephone from November 27-29 among 425 likely Republican caucus-goers. It has a sampling error of plus-or-minus 4.8 percentage points.
The NBC News/Marist in New Hampshire was conducted by telephone from November 28-30 among 696 likely Republican primary voters. It has a sampling error of plus-or-minus 3.7 percentage points.