Live updates: US on razor's edge as Americans begin voting

Surveillance drones hovered overhead and snipers on rooftops kept a close watch as millions of Americans headed to the polling stations on Tuesday in one of the tightest and most divisive US presidential elections in history.

Vice President Kamala Harris and Republican nominee Donald Trump are locked in a dead heat nationally, with most polling showing them narrowly split by between one and three percent, well within the margin of error on most of the surveys.

Trump winning would make him the first incoming president to have been indicted and convicted of a felony.

Trump would also become only the second president in history to win nonconsecutive White House terms, after Grover Cleveland in the late 19th century.

Harris is vying to become the first woman, first Black woman and first person of South Asian descent to reach the Oval Office.

Officials have implemented extensive security measures at polling and counting centres nationwide in a bid to ensure secure voting.

To further tighten security, additional police units have been dispatched to streets across the country.

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1100 GMT — Polls open in eight US states

Eight states from the eastern US have opened polling stations, including those in Connecticut, New Jersey, New York, New Hampshire and Virginia.

New Hampshire's township of Dixville Notch voted at midnight, continuing a long-standing tradition while splitting the six votes evenly, resulting in a tie.

The midnight voting tradition is believed to have originated to allow railway workers to cast their votes, as their work schedules prevented them from doing so during regular hours.

Almost all polling stations in Maine opened on time, though several municipalities with fewer than 500 residents may open later.

In states such as Indiana and Kentucky, polls have begun opening. However, some regions in these states will not open until 7 am.

1000 GMT — Vermont becomes first US state to open polls

Americans begin voting in parts of Vermont, the US state bordering Canada, at 5 am local time.

Polls in different towns of the state open from 5 am to as late as 10 am.

The tiny New Hampshire resort town has a tradition dating back to 1960 of being the first in the nation to complete in-person voting.

The town’s six voters began casting their ballots on the stroke of midnight Tuesday and the vote count was complete 15 minutes later.