Columbia, United States - Hillary Clinton defeated Bernie Sanders by an overwhelming margin in Saturday's Democratic primary in South Carolina, projections showed, seizing momentum ahead of the most important day of the nomination race: next week's "Super Tuesday" contests.
After a series of single state contests, the former secretary of state was seeking a decisive win in the first southern state to vote for a 2016 Democratic presidential nominee, before the race goes national on Tuesday with contests in 11 different states.
Exit polls suggest she earned just that. US networks called the race for Clinton moments after polls closed in the Palmetto State, where the majority of Democratic voters are African-American, a voting bloc that she has successfully courted for decades.
"To South Carolina, to the volunteers at the heart of our campaign, to the supporters who power it: thank you," Clinton said on Twitter shortly after the projections were made.
The win marks a moment of redemption for Clinton, who in 2008 lost badly in the state to Barack Obama, whose victory here served as a turning point for his own campaign.
Clinton supporters gathered in Columbia to hear her victory speech issued a loud cheer when the result was called.
Very early results, based on four per cent of precincts reporting, suggest she won the state by 78.5 per cent compared to 20.9 per cent for Sanders. Citing exit polls in South Carolina, CNN said African-American voters backed Clinton by a stunning 84 per cent, against 16 per cent for Sanders.
Saturday's result was a foregone conclusion of sorts, with Sanders bolting from the state Saturday morning to head to Texas and then Minnesota, two states in play next Tuesday when Sanders is aiming to keep his head above water if he wants to challenge Clinton deeper into the nomination race.
Sanders swiftly offered his congratulations, but insisted he was in it for the long haul.
"Let me be clear on one thing tonight. This campaign is just beginning," he said in a statement.
"We won a decisive victory in New Hampshire. She won a decisive victory in South Carolina. Now it's on to Super Tuesday."
Among Democrats, Clinton leads in the national delegate count at this early stage, having now won three of the first four nomination contests - in Iowa, narrowly, then Nevada and South Carolina.
As the Democrats voted, the Republican churned on with frontrunner Donald Trump trading barbs with rival Marco Rubio, who in recent days has launched a fierce assault on the billionaire real estate mogul.
"I want to save the (Republican) party from a con artist," Rubio, seen by many as the man best-positioned to topple Trump, said at a stop in Kennesaw, Georgia.
Rubio accosted Trump for "flying around on hair force one," and having "the worst spray tan in America."
Trump pushed back during a speech in Arkansas, one of the dozen states voting Tuesday.
"I watched this lightweight Rubio, total lightweight, little mouth on him, bing, bing, bing," Trump sneered.
"I'm a con man, right? I built a great business!" The brawling among Republicans may reinforce Clinton's argument that she has the temperament and experience to be commander in chief.
"When you are president, the entire world listens to every word you say," Clinton said in Birmingham, Alabama, in an apparent attack on Trump's badgering of rival candidates and his caustic remarks about immigrants and Muslims.
Sanders, a self-declared democratic socialist who represents Vermont in the US Senate, headed earlier Saturday to Texas, where he told some 10,000 people that he has been this election's comeback kid.
Sanders is also focusing on states like Ohio and Minnesota that vote later in March, when a whopping 45 per cent of the delegates who will attend the nominating convention are up for grabs.
Only three per cent of delegates for July's nominating convention in Philadelphia will have been awarded by Saturday's end.
But the 11 states that hold Democratic nominating contests next Tuesday will send a whopping 18 per cent of the delegates to Philadelphia.
Clinton is ahead in most, but Sanders has the edge in Massachusetts and his home turf of Vermont.
Retired teacher Elvira Kennedy, 70, voted for Clinton in Columbia.
"She's the best candidate," said Kennedy, who is African-American.
"We never had a woman president, it's about time we give a woman a chance to mess everything. Men have been doing it for 300 years."