Seven Republicans seeking to unseat U.S. President Barack Obama in the 2012 election will meet in their first major debate later Monday.

The nationally televised forum on CNN will be held in New Hampshire, where the candidates already are campaigning, months ahead of the first voting contests early next year.

According to a CNN/Opinion Research Corporation survey released Monday, former Massachusetts governor Mitt Romney has the support of 24 percent of Republicans and independents who lean toward the party.

Former Alaska governor Sarah Palin is second with 20 percent, followed by former New York mayor Rudy Giuliani. Palin and Giuliani, who both have not said whether they are running, are not taking part in Monday's debate.

Among those hoping to steal the spotlight from Romney are former House speaker Newt Gingrich, former Minnesota governor Tim Pawlenty, and current Minnesota Representative Michele Bachmann. Bachmann, a favorite of the Tea Party movement, has not yet declared her candidacy.

Businessman Herman Cain of Georgia, Representative Ron Paul of Texas and former senator Rick Santorum of Pennsylvania again will join a presidential debate. They participated in a South Carolina debate that Romney and others skipped earlier this year.

Former Utah governor Jon Huntsman, who recently resigned as Mr. Obama's ambassador to China, will not be present, even though he is expected to join the race.