• Most US states permit early voting to deal with scheduling conflicts.
• Trump blames mail-in ballots for his 2020 defeat to Joe Biden.
  
• Early voters line up at polling stations ahead of Nov 5 US polls.

ARLINGTON: The first early voters cast their ballots Friday for November's knife-edge US presidential election, as Democratic candidate Kamala Harris headed for a campaign event focused on the hot-button issue of abortion.

Three US states — Virginia, Minnesota and South Dakota — were starting early voting, a practice that Republican nominee Donald Trump has previously cast doubt on when falsely claiming he won the 2020 election.

Dozens of people waited at an early voting polling station in the centre of Arlington, Virginia, just outside the capital Washington, AFP journalists saw.

A number had "Harris-Walz" shirts, while there were also some "Trump-Vance" signs in front of the building.

"I'm excited," said Michelle Kilkenny, 55, adding that voting early, "especially on day one, helps the campaign and raises the enthusiasm level."

Most US states permit in-person voting or mail-in voting to allow people to deal with scheduling conflicts or an inability to cast their ballots on election day itself on November 5.

Former President Trump has frequently lashed out against anything other than on-the-day voting, repeatedly blaming mail-in ballots for his 2020 defeat to Joe Biden. He has also, at times, questioned early voting, despite efforts by his campaign to promote it.

Trump, 78, faces criminal charges for allegedly trying to overturn the 2020 election result, after which his supporters assaulted the US Capitol on January 6, 2021.