Live updates: US capital takes precautions for potential election unrest

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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1329 GMT — DC braces for potential election-related violence

Businesses around the White House continued to board up windows and erect temporary fencing, precautions being taken amid worries that Election Day — and the days ahead — could lead to unrest.

DC Mayor Muriel Bowser says the police department is also stepping up its presence in commercial districts in all eight wards of the city.

Metropolitan Police Chief Pamela Smith at a news conference also sought to assure the city’s residents that her department is prepared for whatever Election Day might bring.

"Our team has been fully engaged and vigilant," she said. "We are the best in the country at what we do, and we will keep working around the clock to keep Washington, DC, safe and keep our residents safe."

1325 GMT — Most Florida voters cast their ballot before Election Day

When polls opened at 7 am local time in Florida, a majority of the state’s registered voters had already cast a ballot early — including voting by mail and early in-person voting, according to an analysis of state data by the University of Florida Election Lab.

Of those who waited to vote on Election Day, many were getting their civic duty out of the way early, according to elections officials.

In Orange County, home to the city of Orlando, more than 4,700 people voted in the first 20 minutes of polls being open, according to a social media post by the county elections supervisor’s office.

1323 GMT — DNC rolls out Election Day ads to boost voter turnout

The Democratic National Convention has launched an Election Day persuasion campaign urging people to vote.

It includes more than 100 new billboards in battleground states, including 34 in Pennsylvania and 32 in Nevada, and 300 digital kiosks targeting college campuses in Pennsylvania, Wisconsin and Michigan.

In Pennsylvania, voters will see the ads in more than 1,700 convenience stores.

1315 GMT — Over 4 million voters in Georgia cast early votes

The early turnout in Georgia, which has flipped between the Republican and Democratic nominees in the previous two presidential elections, has been so robust — over 4 million voters — that a top official in the secretary of state's office said the big day could look like a "ghost town" at the polls.

As of Monday, Associated Press tracking of advance voting nationwide showed roughly 82 million ballots already cast — slightly more than half the total number of votes in the presidential election four years earlier.

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.