Republican John McCain and Democrat Hillary Clinton looked on Sunday toward the next battles in a chaotic White House race after scoring tough wins in the first presidential voting in the US South and West.
McCain narrowly defeated rival Mike Huckabee on Saturday in South Carolina -- a state where McCain's presidential hopes were destroyed in a bitter 2000 battle that set George W Bush on a path to the White House.
"It took us a while, but what's eight years among friends," McCain, an Arizona senator, told cheering supporters in Charleston. "We are well on our way tonight, and I feel very good."
In Nevada's Democratic race, Clinton beat Barack Obama in a close struggle that featured voting in the state's famed casino hotels. The pair had split the first two Democratic contests and ended up disputing who held the upper hand.
"I guess this is how the West was won," Clinton, a New York senator, said in Las Vegas. She told reporters later, "This is one step on a long journey throughout the country."
Although Clinton won more votes, Obama said that because of his strength in some areas outside Las Vegas, he would have the support of 13 delegates to Clinton's 12 to August's Democratic convention. Delegates select the presidential nominee.
Nevada Democratic Party head Jill Derby issued a statement saying Obama had the edge if the delegate count held, but this would only be decided finally between now and April.
Mitt Romney, the former Massachusetts governor, won a Republican race in Nevada that his rivals largely skipped in order to concentrate on South Carolina.
No candidate in either party has claimed the front-runner's role in the race to pick the two candidates to contest the November 4 election to succeed Bush, as the first major state-by-state battles produced multiple winners.
The US presidential nominating battle now turns to the South, where the next fights will be South Carolina's Democratic primary on Saturday and Florida's Republican primary on January 29.
Then both parties turn their attention to the February 5 "Super Tuesday" round of 22 state contests, a massive shift from the intimate politics of early voting states to coast-to-coast flights and big-budget advertising campaigns.
Clinton's first stop after her Nevada victory was in St Louis, Missouri, a state that will vote on February 5.
"Talk to your friends and neighbors. Make it clear that we're going to be picking a president on February 5 and we have to pick someone who can be ready to lead on day one," Clinton said.
Obama, an Illinois senator who would be the first black US president, leads polls in South Carolina, where more than half of the primary voters are expected to be black.
The Florida Republican race will mark the debut of former New York Mayor Rudy Giuliani, who has seen his once-substantial lead in national opinion polls disappear as he sat on the sidelines through the first presidential nominating contests.
Giuliani has gambled that a win in Florida will propel him to a strong day on February 5 in populous states like New York, California, New Jersey and Illinois.
For the victors on Saturday, the prize was a jolt of energy in a race where momentum has been short-lived.
Clinton, who would be the first US woman president, won the Nevada Democratic race, 51 per cent to 45 per cent over Obama, with turnout reported to surpass 115,000 voters. Former North Carolina Sen John Edwards finished a distant third.
"We ran an honest, uplifting campaign in Nevada that focused on the real problems Americans are facing, a campaign that appealed to people's hopes instead of their fears," Obama said in a statement.
"That's the campaign we'll take to South Carolina and across America in the weeks to come," he said.
McCain's win in South Carolina, which followed a New Hampshire victory, was fueled by support from conservatives, with exit polls showing 7 in 10 voters in the state primary described themselves that way.
More than half of the voters were religious conservatives, but that was not enough to give the win to Huckabee, a former Arkansas governor and Baptist preacher whose Iowa win was fueled by evangelical support.
The win was another step on the comeback trail for McCain, a former Vietnam prisoner of war whose presidential bid seemed finished last summer when he was low on cash, shedding staff and sinking in the polls.
South Carolina Republicans have been kingmakers in party politics, with the Republican winner in the state going on to capture the party's nomination every year since 1980.