Former Massachusetts governor Mitt Romney has narrowly won the first vote by US Republican party supporters in the process to choose a presidential candidate for this year's election.
He finished just eight votes ahead of former senator Rick Santorum in the Midwest state of Iowa.
Ron Paul came third, while Newt Gingrich and Michele Bachmann settled into a second tier of candidates.
Rick Perry is considering the future of his campaign after finishing fifth.
The caucus meetings were the first time voters had a say in the race to face Democratic President Barack Obama in the 6 November presidential election.
Tuesday's contest launched months of caucuses and primary elections in 50 states, Washington DC and other territories, culminating in the Republican National Convention in August where the party nominee will be formally anointed.
Iowa was not expected to settle the contest - John McCain, the eventual Republican nominee in 2008, came fourth in the state's caucuses that year - but it will help shape the race for the White House.
The BBC's Mark Mardell says that in the end, this result has to be good for Mitt Romney, achieving it in a state he hadn't bothered to fight until the last few weeks.
bbc.com
