The surge in early voting comes amid a stubborn novel coronavirus pandemic that has led to a surge of early and mail balloting, particularly among Democrats, Reuters reported.

Republican US President Donald Trump has sowed confusion and distrust of mail balloting, making repeated, unfounded allegations of widespread fraud ahead of his contest with Democratic nominee Joe Biden.

As of last night, nearly 10.4 million Americans have cast a vote in states that report early voting data, according to the election information resource at the University of Florida.

By way of comparison, as of October 16, 2016, some 1.4 million Americans had cast an early vote.

The number of ballots cast in five states — Minnesota, South Dakota, Vermont, Virginia and Wisconsin — already exceeds 20 per cent of total 2016 turnout, the Elections Project said.