The Republican National Committee (RNC) has filed a lawsuit in Cambria County, Pennsylvania, following the extension of voting hours earlier.

The lawsuit supports the emergency petition to extend the voting hours, after a key software malfunction meant the scanners weren't working.

This led to delays and long queues for voters.

RNC chairman Michael Whatley says voters should stay in line.

"This morning's ballot processing issues in Cambria have resulted in delays - this is unacceptable, plain and simple," he adds.

Image source, EPA-EFE/REX/Shutterstock

There were five non-credible bomb threats at polling locations in Fulton County, Georgia, this morning, reports CBS, BBC's US media partner.

Nadine Williams, the county’s director of registration and elections, says the threats led to the temporary evacuation of two locations for approximately 30 minutes each in the swing state.

The county, which includes the city of Atlanta, is now working to obtain a court order to extend the hours of the two affected locations until 19:30 local time (00:30 GMT Wednesday).

We reported earlier that technical issues in Cambria County, Pennsylvania, had prevented some voters from scanning their ballots, and electoral officials in that battleground state also filed a court order to extend the voting time.

Bernd Debusmann Jr
Reporting from Philadelphia

I just left the offices of the Philadelphia District Attorney's Election Task Force, which has about 60 assistant district attorneys assigned to investigate any complaints about the electoral process in the city.

In a brief news conference, officials said that the task force has so far received "dozens" of reports, primarily about people intentionally blocking access to polling sites.

District Attorney Larry Krasner said the behaviour is "a little more aggressive" than in previous elections in the city, although the issues have so far been resolved without incident.

Officials are also investigating social media posts which purport to show interactions with workers and the inside of polling locations - potentially making them violations of state wiretap and election security laws.

No arrests have so far been made.

Krasner - a Democrat - delivered a strong warning at the outset of his remarks, and pointed at staff members who printed, overnight, T-shirts marked with the acronym FAFO - or "F Around and Find Out".

"There are handcuffs. There are cells. There are courtrooms, and there are Philadelphia jurors who will want to know why it is a person tried to erase their votes, block their votes, bully their votes or take away their votes."

Kayla Epstein
Reporting from Florida

We’re still waiting for Trump at his West Palm Beach polling site, but Rudy Giuliani, his erstwhile personal lawyer, has pulled up in a slate blue convertible.

He wore an American flag shirt and was immediately mobbed by press and supporters. Like many snowbirds, the ex-New York City mayor has a condominium here in Florida.

Giuliani is still facing repercussions from his attempts to overturn the 2020 election results on behalf of Trump.

He was ordered to pay two Georgia poll workers nearly $150m (£115m), after he was held liable for defamation for spreading falsehoods that they committed election fraud. A federal judge recently ordered him to hand over his Manhattan apartment and luxury items to the women via a receivership.

Giuliani has also been indicted in Georgia and Arizona over charges he attempted to meddle in each state’s 2020 election results. He has pleaded not guilty.

Sam Cabral
Reporting from Washington DC

In a race as close as this one, early vote returns this evening may not be the best indication of a candidate's momentum or who will eventually win.

Think back to the 2020 election, when Donald Trump was leading in some key states on election night but Joe Biden overtook him as mail ballots, heavily favoured by Democrats at the time, were counted. Though election experts warned beforehand of such a phenomenon, Trump seized upon it to amplify his unfounded claims that the election was stolen.

There could be another so-called "red mirage" this year - or perhaps a "blue mirage" that initially favours Kamala Harris but then shifts toward Trump.

More than 83 million Americans have already voted, according to the University of Florida Election Lab's nationwide early vote tracker.

Women make up 54% of that tally, which could be a good sign for Harris. But while early voting has typically favoured Democrats, registered Republicans have cast nearly as many early votes this time around.

There is also an X factor - the Trump campaign has hinted he could prematurely declare victory if his team believes he has crossed the threshold of 270 Electoral College votes needed to win the presidency.

So when will we know who won?

Voting is under way in all seven swing states. Let’s take a look at the latest polling data to see where we are at in each of them.

The leads continue to be too small to effectively say who's ahead, and it's important to factor in a margin of error of about three to four percentage points.

However since our last report earlier today, polls suggest that Harris has taken the lead in the key swing state of Pennsylvania, where the candidates were previously tied.

The Keystone State is considered by some pundits to be the biggest prize on the electoral battleground map and Harris and Trump have inundated the state with campaign stops.

Trump still has a small lead in Nevada, Georgia, North Carolina, and Arizona, with similarly minor leads for Harris in Wisconsin and Michigan.

• You can continue to follow the latest polling data here

Bernd Debusmann Jr
Reporting from Pennsylvania

Tens of millions of voters will step into ballot booths across the United States on Tuesday.

But the results of the election - including whether Kamala Harris or Donald Trump will be the next president - will not be official until votes are counted and verified, which could take days to complete.

The first polls will begin closing as early as 18:00 EST (23:00 GMT) in certain counties on Tuesday, but counting votes will extend hours beyond that in most states.

For instance, in two battleground states - Pennsylvania and Wisconsin - election workers are not allowed to begin processing mailed-in ballots until election day.

That is expected to slow the effort.

It's important to note that news organisations use unofficial results and projections when they announce winners on election night or the following days, instead of waiting for the final and official count.

Some counties "feed" ballots into optical scanners, while others may use touch-screen systems or ballot-marking devices to record votes.

The scanners are the most common. They tabulate results, which are then manually recounted and double-checked by hand.

We have a handy guide about how the election results are counted.

The clocks have just turned 07:00 local time in Alaska and 08:00 local time in Washington state, meaning that polling stations are now open.

There are three electoral college votes up for grabs in Alaska, America's largest state by land, and there are 12 electoral college votes available in Washington, the lumber producer of the US.

Hawaii - with four electoral college votes - has the honour as the final US state to open its polling booths with voting to begin at 07:00 local time (17:00 GMT).

And to get a sense of just how big America is, and the various time differences across the country, voting in Hawaii starts just seven hours before the first polls close on the East Coast.

Jamie Coomarasamy
Reporting from Milwaukee, Wisconsin

Married couple Roger and Laura are among the more than 80 million Americans who have voted early.

Speaking to us in Solly’s Grille, a diner in northern Milwaukee, Laura says she’s a Harris voter.

She explains that she doesn’t want women in America to “go backwards” and hopes that she’s convinced her husband to vote for Harris.

It turns out she didn’t.

Roger says he voted for the “least worst” of the candidates, because he’s a conservative and feels strongly about abortion.

The couple say they don’t speak about politics at home, but Laura says she “hopes” their marriage can be an example for a divided country.

Sam Cabral
Reporting from Washington DC

Image source, Getty Images

Steve Bannon, former chief strategist of the Trump White House, plans to hold an election watch party tonight at the Willard Hotel - the five-star Washington DC hotel that served as the "command centre" for Trump loyalists seeking to overturn the 2020 election results.

Bannon, was released from federal prison one week ago, after serving four months behind bars for contempt of the US Congress.

On 5 January 2021, the day before the US Capitol attack, Bannon and other Trump allies held court in a set of rooms and suites at the Willard, one block away from the White House.

It served as their headquarters for their pressure campaign on Republicans to block the certification of Joe Biden's victory the next day.

Bannon's release from prison and revival of the January 6 "war room" comes as Trump allies have laid the groundwork for legal, political and constitutional challenges to the 2024 results. Top Republicans have also repeatedly refused to say they will accept the election’s outcome if Trump loses.

"Unlike in 2020, we will secure Trump's victory this time," Bannon told CBS News, the BBC's US partner, on Tuesday morning.

Sarah Smith
North America editor

There is a much greater air of unpredictablity around today’s vote than is usual on election day.

With polls still suggesting that it is an exceptionally tight race, no one knows who is likely to emerge the winner.

But that’s not the only question in the US today. We don’t know when a result will be declared, as it could take days to get a final vote count from some of the key battle ground states like Pennsylvania.

There is also trepidation about how people might react to the result. The US National Guard is on standby in Washington state, Oregon and Nevada in case of civil unrest. And security barriers have been erected outside the White House and other sites in the US capital.

Voters say they are exhausted by this tumultuous campaign and want it to be over - but are also apprehensive about what may happen next.

Tension is running high in this a deeply divided nation which is about to make a critical decision.

Brandon Drenon
Reporting from North Carolina

Puddles of water and mud slicked roads led the way for Debra Kendrick and her husband, Robert, who showed up on Tuesday morning in the rain to cast their vote for Donald Trump, inside of a tent in western North Carolina.

The tent was installed to replace a damaged polling location elsewhere in Buncombe County, which absorbed much of the destruction from Hurricane Helene.

Though the Kendrick’s home was not destroyed, all of the roads leading into their town were, Debra says. The hurricane left them stranded at home in darkness for days.

They couldn’t evacuate the area until someone came to rescue them via canoe.

None of this would stop them from casting their ballots weeks later. “I’m just glad we have a place to be able to vote,” Robert says. “It’s a very important election. “We feel like the country is going the wrong way."

"The crisis at the border, [the Biden-Harris administration] is not controlling it. That’s probably the biggest thing.”

Image source, Getty Images

We saw Trump's running mate JD Vance turn up to vote in Cincinnati, Ohio, a little earlier - we can bring you an update now on what he had to say.

The Republican candidate for vice president told the press that he expects Trump to win, but acknowledged that, whatever the result, half the country is going to be "at least partially disappointed".

"My attitude is, the best way to heal the rift in the country is to try to govern the country as well as we can, create as much prosperity as we can for the American people, and remind our fellow Americans that we are all fundamentally on the same team, however we voted," he says.

Bernd Debusmann Jr
Reporting from Pennsylvania

As election day enters its fourth hour in Pennsylvania, we've been hearing from voters in Cambria County - where technical glitches have been reported.

A local woman, Jessenia Anderson, texted me earlier to say that voting machines were down - and that "scanners aren't working".

"People are voting and leaving their ballots either face down or placing them in a lock box under the scanner," she said.

Similar incidents were reported on X, formerly Twitter.

In a statement, the Cambria County Board of Election said that a "software malfunction" had prevented some voters from scanning their ballots.

"This should not discourage voters from voting at their voting precincts," the statement added.

The board has filed a court order extending the time to vote in the county - which is located near Pittsburgh.

"There is a process in place for issues of this nature," the county said. "All completed ballots will be accepted, secured and counted."

Issues have also been reported in Allegheny County, which includes Pittsburgh. In at least two cases, the county says that electoral officials were delayed arriving at their designated polling places.

Ana Faguy
Reporting from Washington DC

Who should be the next president won't be the only thing on the ballot today.

Millions of voters in Montana, Arizona, Missouri, Nebraska, Colorado, Florida, Maryland, Nevada, New York and South Dakota will be asked how their state should regulate abortion.

Most of the initiatives in those 10 states would allow abortion until foetal viability, which is generally considered about 24 weeks, or later only in instances when the health of the pregnant woman is at risk.

The efforts are a response to the Supreme Court's 2022 decision to overturn Roe v Wade, which led many states to enact abortion restrictions or bans. Pro-choice advocates hope that by having voters directly decide to enshrine abortion in states' laws, they can bypass the ups and downs of state courts.

But there's another reason why some want abortion on the ballot - voter turnout.

Democrats hope that more people who support abortion rights, who overwhelmingly back their party, will show up on election day because the issue is on the ballot.

Here’s what the each of the questions look like.

Kayla Epstein
BBC reporter in West Palm Beach, Florida

Image source, Getty Images

Here in Florida, there’s another big item on the ballot: Amendment 4, which would enshrine abortion rights in the state constitution.

If passed, it would overturn the six-week abortion ban currently in effect here and expand access to the point of foetal viability, which is about 24 weeks of pregnancy.

But it has the highest threshold for passage: 60%. Polls suggest Floridians support the amendment, but the campaign is short of that number.

Florida is one of 10 states with abortion measures on the ballot today.

Democrats are also hoping abortion measures on the ballot in battleground states like Arizona will drive turnout for Harris and other Democrats.

But in Florida, a vote for abortion rights doesn’t automatically equal a vote for Harris.

I met several people who were voting "yes" on 4 and "yes" to Trump.

Jonel Jones, 37, is one voter who is splitting her ballot that way.

While she does not believe in abortion, she has read stories from other states about pregnant women who became sick or died after being denied abortion or miscarriage treatment.

"I don’t think it’s right," Jones says.

Read more from Kayla here

Lily Jamali
Reporting from Nevada

Image source, Ben Derico

Nevada has attracted its fair share of canvassers from out-of-state. Many have headed to the Silver State from next door in California, where the Democrats are all but certain to win.

Pro-Harris Californians were among 150 volunteers and staffers at a canvassing event in East Las Vegas late Monday.

"I had to put myself physically into the work and not just write checks or argue over dinner tables," Peter Brock of Fairfax, California, tells the BBC.

He believes he's had some success swaying potential voters in Nevada to vote for Kamala Harris, but he says he's noticed there's a lot of election fatigue among people he's met knocking on doors.

Another Californian, Laura Ponchick from Los Angeles, says she's shocked by how many people remained undecided on the Monday before Election Day, adding that she's enjoyed being able to talk to potential voters in person.

"I was really bracing for the worst. I feel like this election has been very heated, and it's brought out the ugly in everyone. People were a lot kinder than I was expecting," she says.

Image source, Getty Images

We just reported that polls have opened in Nevada - that’s the final swing state to start voting today.

Let’s take this moment to look at what’s happened so far:

• Almost all states are now voting. Voters in Alaska and Hawaii will start to head to the polls in the next hour or two
• Polls will close at different times in different states, but by 23:00 on the East Coast in the US (04:00 GMT) all states will have closed their polls - except for Hawaii and Alaska where polls close an hour later.
• This is not just a race between Trump and Harris. Various states are also voting on other issues such as abortion rights, members of the US Senate and House of Representatives, recreational or medical marijuana, and referendums on voting and elections
• And where are Donald Trump and Kamala Harris today? Trump has headed back to Florida, where he will cast his vote in a little while. Harris is planning to attend an election night party at Howard University, her alma mater.

Stay with us as we bring you all the latest updates.

Kayla Epstein
US reporter

Kamala Harris has been making explicit appealsto women in the suburbs, and in states with abortion legislationon the ballot.

Outrage over the overturning of Roe v Wade helped Democrats to a better than expected midterm election in 2022. Now, Harris is hoping that anger will translate into a presidential victory as well, and has placed abortion rights front and centre in her campaign.

The strategy rests on convincing women in battleground states - like Wisconsin, Arizona and Pennslyvania - to make abortion access the number one issue when casting their ballot.

One state to watch is Arizona, where an amendment to expand abortion access until foetal viability is on the ballot. Democrats are hoping that the measure will drive turnout in the critical battleground state.

It’s also important to watch the suburban areas in battleground states like Pennsylvania, including around Pittsburgh and Philadelphia, where Harris is betting college-educated women will be motivated to vote for a candidate who wants to protect abortion access.

Jamie Coomarasamy
In Ozaukee County, Wisconsin

On the stroke of 07:00 local time (13:00 GMT), a line of voters inside Mequon City Hall is greeted with a call of “oh yay, welcome to the election ” by Nancy, the official in charge.

She tells us that 70% of registered voters in this part of Wisconsin’s Ozaukee County voted early, either in person or by mail.

Unlike four years ago, those early voters weren’t able to leave their papers in voting drop boxes in the streets - because of security concerns.

Ozaukee is one of three suburbs of Milwaukee that have traditionally voted Republican. It is also where Democrats have made inroads during the Trump era - especially among women.

One woman emerging from the polling station tells us she grew up in a Republican family and had voted on the party line in the past, but it was “Kamala all the way, because Trump is for himself”.

Another, younger woman, who voted for Donald Trump, says she is worried about border security and the republican candidate has been misrepresented on abortion.