Joe Biden has won the Arkansas primary, adding to his growing Super Tuesday win totals in the battle to secure the Democratic nomination for president.

The Associated Press called the race , after the former vice president won several other Southern states, including Alabama, North Carolina, Tennessee and Virginia. Arkansas had 31 pledged delegates at stake in the primary, and it's not yet clear which candidates will meet the 15% threshold to share in the haul.

The former vice president held off a surge from former New York City Mayor Mike Bloomberg, who was also seeking to secure moderate Democratic votes. Jay Barth, professor emeritus of political science at Hendrix College, said in an analysis of a poll last month that strong numbers for the mayor could be attributed at least in part to his television advertising campaign, in which he has spent hundreds of millions of dollars.

"While the other candidates have had major national coverage, Bloomberg has had the airwaves to himself in Arkansas," Barth said.

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Jacob Kauffman, political director for the Democratic Party of Arkansas, also noted Bloomberg's campaign had made several visits across the state leading up to Tuesday's primary.

"So people have noticed his presence, certainly," he tells U.S. News.

Kauffman adds that Elizabeth Warren saw a "tremendous upswing" in excitement from state voters and that Bernie Sanders had a "very large" volunteer presence in Arkansas despite no paid field staff.

But in the end, a recent surge by Biden after his decisive win Saturday in South Carolina contributed to an impressive night for the former vice president, whose campaign appeared to be flagging after poor showings in Iowa, New Hampshire and Nevada.

Kauffman said ahead of the primary results that turnout was solid in the state's Democratic strongholds.