The former U.S. ambassador to China, Jon Huntsman, is the latest Republican to begin competing for his party's nomination for president.

Officials told The Associated Press on Tuesday that Huntsman, a former governor of Utah, will officially join the field of Republicans hoping to defeat Democratic President Barack Obama in the 2012 election and will announce it June 21.

Huntsman is seen as a long-shot candidate, as he has little national name recognition, and it could be a disadvantage with conservatives that he was appointed by Obama to the China post. But as a moderate, if he does secure the nomination, he could be a formidable rival to Obama.

Huntsman's move came a day after Republican presidential hopefuls targeted Obama's handling of the economy in their first major debate of the campaign season in Manchester, New Hampshire.

The state will host the first primary of the 2012 campaign.

Former Massachusetts Gov. Mitt Romney appears to be the party's early front-runner, but the field is still unsettled.

Recent polls show Romney to be the Republican in the best position to defeat Obama in November 2012, but it's not clear that he can win over the party's right wing and secure the nomination.

Rivals have criticized him for a Massachusetts health care law that requires people to obtain health insurance because it served as a model for Obama's 2010 health care overhaul that many conservatives detest.

The Republicans who shared a stage with Romney on Monday night were plainly more interested in criticizing Obama than one another. Obama, who remains popular, could be vulnerable in the 2012 race due to the staggering economy, high unemployment and steep gasoline prices.

Huntsman's entry has been expected since he left his ambassador's post in the spring and began putting together a campaign organization.

He, too, could have difficulties with the conservative base because he's seen as a moderate. Also, like Romney, he's a Mormon, which could alienate some voters.

On Sunday, former Minnesota Gov. Tim Pawlenty had derided the Massachusetts health law as "Obamneycare," a play on critics' term "Obamacare" for the president's health reform. But Pawlenty seemed loath to revisit the issue Monday.

Pressed by the moderator three times to explain his use of "Obamneycare," Pawlenty replied somewhat weakly that it was "a reflection of the president's comments that he designed Obamacare on the Massachusetts health care plan."

If any candidate had nearly as good an evening as Romney, it was Rep. Michele Bachmann of Minnesota. She made maximum use of CNN's live telecast to announce she was formally entering the race.

She drew one of the loudest rounds of applause Monday night from a partisan debate audience when she predicted that Obama would be "a one-term president." She is popular with social conservatives which makes her a credible threat to other candidates courting core Republican voters.

Asked on the CBS's "The Early Show" on Tuesday how she would feel about former Republican vice presidential candidate Sarah Palin getting into the race, Bachmann said: "I think we have room for more if the governor chooses to get in."

The seven Republican candidates found little if anything to like in what the president has done since taking office in the midst of the worst economic recession since the Great Depression of the 1930s.

"When 14 million Americans are out of work we need a new president to end the Obama Depression," said former House Speaker Newt Gingrich.

Gingrich was trying to revive his campaign after suffering the mass exodus of the entire top echelon of his staff last week, an unprecedented event that left his chances of winning the nomination in tatters.

Other candidates who participated were former Sen. Rick Santorum, businessman and political novice Herman Cain and U.S. Rep. Ron Paul.

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AP writer Philip Elliott contributed to this story.