Updated: 3:26 p.m.

Mississippi Gov. Haley Barbour announced Monday that he will not seek the presidency in 2012, a surprise move sure to send ripples through the evolving Republican field.

In a statement released Monday afternoon, he suggested that he didn’t have “the fire in the belly” to run for the White House, despite having staff in place in early primary states and a national fundraising network.

“I will not be a candidate for president next year. This has been a difficult, personal decision, and I am very grateful to my family for their total support of my going forward, had that been what I decided,” he said.

“Hundreds of people have encouraged me to run and offered both to give and raise money for a presidential campaign. Many volunteers have organized events in support of my pursuing the race. Some have dedicated virtually full time to setting up preliminary organizations in critical, early states and to helping plan what has been several months of intensive activity.

“I greatly appreciate each and every one of them and all their outstanding efforts.  If I have disappointed any of them in this decision, I sincerely regret it.”

Barbour is the former chairman of the Republican National Committee and the Republican Governors Association. His decision comes roughly one week after he made his first trip this cycle to New Hampshire.

Barbour continued: “A candidate for president today is embracing a ten-year commitment to an all-consuming effort, to the virtual exclusion of all else. His (or her) supporters expect and deserve no less than absolute fire in the belly from their candidate. I cannot offer that with certainty, and total certainty is required.”

Barbour had been making all the moves associated with a White House bid, including a recent trip to New Hampshire where he said he expected to “do well” in the first-in-the-nation presidential primary.