United States President Donald Trump, a Republican, has claimed to have won and vowed to launch a Supreme Court challenge, baselessly alleging fraud.

Earlier, Trump’s challenger Joe Biden, a Democrat, said he was “on track” to victory.

Millions of votes remain uncounted and no candidate can credibly claim victory as yet.

There is no evidence of fraud.

More than 100 million people cast their ballots in early voting before election day on Tuesday – setting US on course for its highest turnout in a century.

With the nation on edge, the final result may not be known for days.