Rick Santorum has overwhelmingly won the Kansas presidential caucuses as he tries to blunt Mitt Romney's momentum in the grinding campaign for the nomination to oppose US President Barack Obama in the November election.
Santorum, a former Pennsylvania senator, was considered the favourite in Kansas, where his staunch opposition to abortion and gay marriage resonated with the state's large bloc of evangelical voters.
He hoped his victory would give him an advantage in Tuesday's pivotal primaries in the southern states of Alabama and Mississippi where polls show he is dividing the most conservative vote with Newt Gingrich.
A total of 52 delegates to the Republican National Convention was at stake on Saturday, 40 in Kansas and 12 in Wyoming.
Returns from 61 per cent of Kansas' precincts showed Santorum with 53 per cent support, Romney with 17 per cent, Gingrich with 16 per cent, and Ron Paul with 13 per cent.
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Romney was showing strength in Wyoming, where some counties caucused earlier in the week, Romney had five of the 12 delegates at stake, Santorum had two, Paul had one, and one was uncommitted. Three more remained to be determined in party meetings later on Saturday.
Romney, the front-runner by far in the delegate competition, padded his lead Friday night when he won all nine delegates on the island of Guam and an equal number in the Northern Mariana Islands.
Romney did not campaign in Kansas. Santorum and Paul, a Texas congressman, both made stops in the state in the days leading to the caucuses.
Gingrich cancelled a scheduled trip to Kansas late in the week to concentrate on the primaries in Alabama and Mississippi, which the former speaker of the House of Representatives considers friendlier territory.
Santorum hopes that a poor showing by Gingrich in these southern contests will drive the former Georgia congressman from the race and enable him to establish himself as the sole conservative alternative to Romney.
Romney has been benefiting so far because the more conservative vote has been divided between Santorum and Gingrich, enabling him to defeat Santorum by a few percentage points in such key states as Ohio and Michigan.
The former Massachusetts governor continues to fight scepticism among Republican voters about his past, more moderate, views on such sensitive social issues as abortion.
Santorum styles himself as the true conservative in the race, but he lacks the campaign cash and organisation that the multimillionaire Romney, the former CEO of a private equity firm, has at hand.
Romney began the day with 440 convention delegates in the AP's count, more than all his rivals combined. Santorum had 181, Gingrich 107 and Paul had 46.
A candidate must win 1,144 delegates to clinch the Republican presidential nomination at the national convention in Tampa, Florida, next August.
The Virgin Islands also had weekend caucuses.
In sparsely populated Wyoming, there were 15 county conventions during the day to pick six convention delegates. Another six were chosen earlier, with Romney winning 4, Paul one and one uncommitted.
Kansas drew more attention from the presidential contenders, but not much more, given its position midway between Super Tuesday when Romney won six of the 10 state contests and potentially pivotal primaries next Tuesday in Mississippi and Alabama.
In Topeka, Kansas, on Friday, Paul told an audience of about 500 that Kansas should be a "fertile field" for his libertarian-leaning views but declined to say how many delegates he hoped to gain.
Santorum lashed out at Obama and Romney simultaneously in remarks in the Kansas capital city.
"We already have one president who doesn't tell the truth to the American people. We don't need another," he said.
The former Pennsylvania senator told reporters he was confident "that we can win Kansas on Saturday and come into Alabama and Mississippi, and this race should come down to two people."
An aide to Gingrich said earlier in the week the former House speaker must win both Southern primaries on Tuesday to justify continuing in the campaign.
But Gingrich strongly suggested otherwise on Friday as polls showed a tight three-way contest in Alabama.
"I think there's a fair chance we'll win," the former House speaker told The Associated Press about the contests in Alabama and Mississippi. "But I just want to set this to rest once and for all. We're going to Tampa."
Romney had no campaign appearances Saturday. Romney, hopes for a Southern breakthrough in Alabama on Tuesday after earlier losing South Carolina and Georgia to Gingrich, who represented a suburban Atlanta district in the House for two decades.
Despite his constant campaign message of having the business background to fix the economy - by far the biggest issue in this election - Romney has not been able to pull away from his rivals for good.
