Hillary Clinton
Hillary Clinton Reuters

Democratic presidential candidate Hillary Clinton won the South Carolina primary on Saturday, according to projections by several American networks.

With 99% of votes counted as of 10:00 p.m. Eastern Standard Time, Clinton led by a huge margin, 73.5% to 26%, and was ahead by a staggering 174,000 votes, according to CNN.

"To South Carolina, to the volunteers at the heart of our campaign, to the supporters who power it: thank you," Clinton tweeted as CNN, MSNBC and Fox News all called the vote in her favor at the close of polls at 7:00 p.m..

Sanders immediately congratulated his rival, while vowing to fight on for the party's presidential nomination.

"This campaign is just beginning," he said in a statement quoted by AFP.

"We won a decisive victory in New Hampshire. She won a decisive victory in South Carolina. Now it's on to Super Tuesday," added Sanders.

Polls suggested Clinton was heading for a victory margin of more than 27 points, with The Associated Press's exit polls showing that about six in 10 voters were black.

According to CNN, Clinton won the support of 80% of African-Americans who voted. Sanders, meanwhile, topped Clinton by a roughly 60%-40% margin among white voters.

The win in South Carolina follows Clinton's narrow victory a week ago in Nevada.

Following the Nevada vote, Senate Minority Leader Harry Reid announced he is endorsing Clinton for president.

"I think the middle class would be better served by Hillary," Reid said, adding, "I think that my work with her over the years has been something that I have looked upon with awe. She was the first lady. She started the trend toward looking to do something about health care. She understood the issue well, she was the front on the health care during that administration.”.