Doug Jones won 49.9 percent of Tuesday's vote, with the Trump-backed Republican, Roy Moore on 48.4 percent in the special election called after Jeff Sessions left to serve in President Donald Trump's administration.

Jones said he was "overwhelmed" by the win. "I have always believed that the people of Alabama have more in common than divides us," Jones told supporters at his campaign victory rally. "We have shown the country the way that we can be."

Moore refused to concede defeat, saying: "When the vote is this close, it is not over."

With 100 percent of precincts reporting, Alabama Secretary of State John Merrill said turnout was likely not above 25 percent of registered voters.

'Dignity and respect'

"At the end of the day, this entire race has been about dignity and respect," he said, adding that his campaign had been about "finding common ground," and encouraging lawmakers in Washington to work together to fund the children's health insurance program.

Jones becomes the first Democrat in a quarter of a century to win an Alabama Senate seat. US President Donald Trump won Alabama in the 2016 presidential election by 28 points. The Democrats' win means the Republicans' slim majority in the Senate will narrow further.

A civil rights lawyer, Jones had never run for political office. He was best known for prosecuting two Ku Klux Klansmen who killed four black girls in Birmingham's 1963 church bombing.

Trump was uncharacteristically magnanimous, Tweeting congratulations to Jones soon after the result was called.

Moore's controversial campaign

The defeat of Moore, a 70-year-old controversial Christian conservative, spells trouble for US President Donald Trump and his political base, as well as shrinking the Republican majority in the Senate to 51-49, in turn making the passage of Trump's legislative agenda on taxes, healthcare and security more problematic.

Moore — who arrived at the polling station on horseback — dismissed the questions about sexual harassment that have dogged him during the campaign. "We're done with that. Let's get back to the issues," he said.

This year he attempted a political resurrection against party officials horrified by accusations of sexual misconduct with teenage girls when he was in his 30s.

Most of the Republican establishment, Trump included, originally supported Moore's primary opponent, Luther Strange, in September. Trump's former chief strategist, Steve Bannon, was one of the only high-profile Moore backers at that stage. Trump later came out in full support of Moore.

The election renewed tensions between Trump and the Republicans who control Congress, Senate Majority Leader Mitch McConnell chief among them, who called for Moore to abandon the campaign and promised to set up an ethics investigation if he was elected.

Moore was twice ousted as state Supreme Court chief justice. He was removed from his position the first time after he refused to remove a boulder-sized Ten Commandments monument at the state court building. The second time he was permanently suspended for urging state probate judges to refuse marriage licenses to same-sex couples.

jbh/se (AP, dpa, Reuters, AFP)