Mitt Romney has won the Iowa Republican presidential caucuses by just eight votes, edging out Rick Santorum by the slimmest of margins in the first serious test to see who will take on Barack Obama in the next U.S. presidential election.
Romney, the ex-governor of Massachusetts, had been considered the favourite in the race, but he faced strong competition from the ex-senator Santorum.
Registered party members in Iowa's 1,774 precincts assembled in more than 800 locations to vote.
With all precincts reporting after 2:30 a.m. Wednesday, Romney was finally declared the winner, with 30,015 votes, or 24.5 per cent, compared to Santorum's 30,007 votes, or 24.4 per cent.
Romney had addressed his supporters earlier in the night. He said he was looking forward to the next caucuses in New Hampshire and told supporters he would "get the job done."
Ron Paul finished a close third with 21.4 per cent of the vote. In a speech to supporters, he credited his success with voters who refused to put up with the status quo and valued his libertarian ideals of limited government.
"You're doing it because you believe in something," he said.
Organizers had expected solid turnouts in good January weather -- no winter storms or extreme freezing temperatures were expected across Iowa Tuesday night.
Iowa, with a population of just over three million people, is the 30th most populous U.S. state, but as the first state to send a message about which presidential candidate it prefers, the results are considered important and deeply influential to the rest of the race.
U.S. President Barack Obama took Iowa, and the strong start helped propel him past Hillary Clinton to eventually win the Democratic presidential nomination.
In 2008, roughly 120,000 Republicans voted in the Iowa caucuses. Weather could affect those numbers this year, however, with cold temperatures forecast for much of the state.
After the vote Tuesday, Romney and Santorum, along with Newt Gingrich, plan to head straight to New Hampshire for the next battle. Paul said late Tuesday night that he would take two days off the campaign trail.
Romney is strongly in the lead in New Hampshire, the so-called Granite State, and could pull off a victory there even if he doesn't win in Iowa.
Rick Perry, who came in fifth in Iowa, said he would return to his home state of Texas and consider whether to continue his campaign.
