Republican presidential candidate and former Massachusetts Governor Mitt Romney addresses supporters at his Iowa Caucus night rally in Des Moines, Iowa Jan 3, 2012. [Photo/Agencies]

DES MOINES, Iowa - Former Massachusetts governor Mitt Romney won the Iowa Republican presidential caucuses by a mere eight votes over former US senator Rick Santorum, a party official said on Wednesday.

Republican presidential candidate and former Massachusetts Governor Mitt Romney speaks to his supporters as his family stands behind him at his Iowa Caucus night rally in Des Moines, Iowa, Jan 3, 2012. [Photo/Agencies]

Romney's razor-thin, eight-vote margin of victory came out of a total 122,255 votes cast on Tuesday, Iowa Republican Party Chairman Matt Strawn said.

Romney won 25 percent of the vote, or 30,015 votes, in the first contest in the state-by-state battle for the Republican presidential nomination to face Democratic President Barack Obama on Nov 6.

The Republican candidates now head to the New Hampshire primary next Tuesday, where Romney holds a commanding lead in the polls.

Santorum vaulted from the back of the pack to emerge as the latest conservative contender in a Republican race that has been marked by volatility. Ron Paul, a US congressman from Texas with libertarian views and an antiwar stance, came in third place with about 21 percent of the vote.  

Romney is a favorite of the party's business wing, while Santorum appeared to be consolidating the state's large bloc of Christian conservatives.  

Voters gathered in public meetings at hundreds of sites around Iowa such as schools, libraries and churches, listening to speeches touting the various candidates before casting their ballots.