President-elect Joe Biden made his first appointments, naming a group of scientists and experts who will lead his administration's response to Covid-19
However, President Donald Trump is still planning legal challenges to the results in some key states
Biden says it will take time to develop a vaccine, and urges Americans to wear a mask to reduce Covid-19 transmissions
Biden and President Trump both welcome news that a vaccine developed by Pfizer and BioNTech is 90% effective
Biden advisers are discussing who can fill key posts after the Democrat pledged the most diverse cabinet in history
Results from the states of Georgia, Arizona, North Carolina and Alaska are still outstanding
Joe Biden is projected to win in New York.
Trump’s former home state has been a Democratic stronghold for three decades. He lost New York to Hillary Clinton in 2016, and more recently has frequently sparred with Governor Andrew Cuomo over the state’s coronavirus outbreak.
Donald Trump is projected to win Arkansas. The state has voted Republican in every race since 2000.
Image source, Getty ImagesA polling site in Dell City, Texas, home to 413 people
When will we know who’s won Texas and why does it matter?
The “Lone Star” state is one of the most glittering of all the prizes. With 38 electoral votes, it the state with the second largest number after California’s 55.
In 2016, Donald Trump won Texas comfortably, beating Hillary Clinton by nine percentage points. This came as no surprise – Texas has voted Republican in every single election since Ronald Reagan in 1980.
So why, in 2020, is Texas worth highlighting?
Most polls project a Trump win, but some are within the margin error and a small number even suggest Biden is ahead. For the first time in decades, the state is competitive.
The growing Latino population and a surge in young people voting are two reasons why Democrats hope the state will eventually turn blue.
Biden dispatched running mate Kamala Harris to campaign in Texas, where she was joined by Beto O’Rourke, who narrowly failed to unseat Republican Ted Cruz in a 2018 Senate race.
Early voting already surpassed the turnout in 2016.
Polls close at 21:00ET (02:00 GMT), with the result expected to be known on the night.
Polls are about to close in a number of important states.
At 21:00ET (02:00GMT) polls will shut in Arizona, Colorado, Kansas, Louisiana, Michigan, Nebraska, New Mexico, New York, North Dakota, South Dakota, Texas, Wisconsin and Wyoming.
Polling indicates that Arizona could go for Biden, but Democrats have their eyes on an even bigger prize. If Texas, with its 38 electoral college votes goes to Biden, the path to victory for Trump becomes almost impossibly narrow - and the US political map will be remade.
Image source, Getty ImagesGeorgia has decided to send to Congress the first US lawmaker to openly support the QAnon conspiracy theory, according to US media.
Marjorie Taylor Greene overwhelmingly won her seat in northwest Georgia after her Democratic opponent dropped out of the race due to personal issues.
Greene has frequently posted inflammatory content on social media. Among her many false claims is that Jewish philanthropist George Soros is a "Nazi", that former president Obama is a Muslim and that Hillary Clinton is a serial killer.
For those unfamiliar, followers of QAnon believe in a wide-ranging, unfounded conspiracy theory about Trump waging a secret war against elite Satan-worshipping paedophiles in government, business and the media.
Read more:
Florida, once again, is a key state to watch this election - so let's take a moment to cast our eye over the latest exit poll data.
Biden appears to be doing better among women, while Trump leads among men. Biden is also doing better among non-white voters, while white Floridians have favoured Trump.
The Sunshine state's 29 electoral votes will be a big prize for either candidate. So far, 93% of the vote has been counted.
Zhaoyin Feng
BBC Chinese, Washington DC
The mood around the White House is calm - so far
Some polls are still open, but the party is already on at Black Lives Matter Plaza, the square in front of the White House.
A cannabis-covered creature dances to funky music, holding a sign that says: "Potsquatch for President". A band in a trailer is performing go-go music, a Washington DC-born sub-genre of funk. Groups of demonstrators are handing out anti-Trump flyers and stickers.
I meet an impersonator of the North Korean leader Kim Jung-un, who says he’s here to support Trump. Only Trump can protect his country from China’s growing power, the 30-year-old South Korean tells me.
The atmosphere in front of the White House is mostly peaceful at this moment, but the number of demonstrators and police seems to be growing, as is the tension. Police officers appear to have made at least one arrest at the plaza tonight.
With President Trump in the White House, the police force and Secret Service will be watching the situation closely.
This man, dressed as North Korea leader Kim Jung-un, says he supports Trump
Image source, Getty Images
Marianna Spring
Specialist disinformation and social media reporter
It’s been a mostly quiet election day, but a small wave of unsubstantiated claims about voter fraud and dirty tricks is being aimed at the crucial swing state of Pennsylvania.
One video showed a poll watcher being denied entry to a Philadelphia polling station. It has almost two million views on Twitter, and was shared by multiple pro-Trump accounts.
The man in the video was asked by officials to wait outside - with a woman telling him that his “city-wide” poll-watching certificate was not valid in that particular polling station.
The video was authentic, but rather than dirty tricks being covered up, it turns out there was confusion over the rules. Poll watchers used to only be allowed in a certain station, but they can now visit multiple sites across Philadelphia. The man was later allowed into the station with an apology.
Similar videos have been shared using the popular hashtag #StopTheSteal. One seemed to show pro-Democratic signage inside a polling place - a rules violation - but local authorities made it clear that the sign was far enough from the voting station, and thus allowed.
The incidents are not hugely viral - about 20,000 tweets use the hashtag - but they come a day after President Trump himself posted unsubstantiated claims about voter fraud and how it could lead to “violence in the streets” in Pennsylvania. Twitter labelled his tweet as misleading - and stopped it from being retweeted.
Image source, EPAOur partner network in the US, CBS, has spoken to an adviser to Donald Trump who says he's anxious about the president's chances of re-election.
White House officials have told the adviser that battleground states are "within spitting distance" and that they are feeling good about the campaign, albeit "extremely nervous".
The adviser called it a "six state election" and believes that Trump has a good chance in those states. But they said the volume of early voting from Democratic parts of the country is unnerving.
"If Florida goes for Biden, then the game is over. But if Florida does go for Trump, then boy, game on," the person said.
With 93% of votes counted, Florida is currently at 51% for Trump, and 49% for Biden.
Donald Trump is projected to win the state of West Virginia.
The Appalachian state gave Trump the vote in 2016 and also backed Republicans in the four previous races.
Polls have started closing in some states and that means results are being projected. Remember, these predictions are made when enough data has come in to make a pattern clear. That includes months of polling, exit polls on election day and some of the actual votes counted. There could be very long vote counts in some places due to the unprecedented volume of early voting.
There are have been no upsets so far, but the night is young. So who has been projected to win where?
None of these states have changed hands between the Republican and Democratic party from the 2016 election.
What's next? Well, there's no race to be the first broadcaster to project who wins in states.
The BBC is getting its data from polling firm Edison Research. If the BBC and its partners don’t believe there is enough data to project a winner, we won’t do so - even if others do.
In the meantime, we are watching the race in Florida where the race is on a knife's edge but it is too early to project the result for now.
Anthony Zurcher
BBC North America reporter
Image source, Getty ImagesPolls in the eastern half of the US are closing fast now. While Florida appears to be trending toward Donald Trump – on the back of better-than-expected performance among Hispanics in South Florida – attention will shift towards other battleground states.
Joe Biden has taken an early lead in Ohio, although the counties that have been reporting are Democratic ones. However, if he can do better than Hillary Clinton, who lost the state, it could give clues as to how he’ll perform in the nearby states that were much closer – Pennsylvania, Michigan and Wisconsin, in particular.
Georgia continues to look like a tossup, as does North Carolina. Both are pretty much must-wins for Trump. And Texas looms on the horizon. While Florida is the big electoral prize that has been a fixation for Democrats for decades, if the Lone Star State moves to the left, it could herald an even more earth-shattering electoral realignment.
The night is just getting started.
Donald Trump is projected to win in the state of Tennessee.
It has voted Republican since the end of the presidency of Democrat Bill Clinton. In 2016, Trump was 26 percentage points ahead of Hillary Clinton.
Image source, ReutersThe Democrats are hopeful they could take Texas, where these well-dressed voters cast their ballots on Tuesday
On our US election TV special, our colleague Barbara Plett-Usher has been speaking to Tom Perez, chairman of the Democratic National Commitee. They are in Wilmington, Delaware where Joe Biden is watching the results.
He says he's feeling "cautiously optimistic".
Biden has several pathways to success, Perez says. By that, he means there are several ways the Democrat can get the votes to add up to the 270 he needs in the electoral college to get to the White House. Remember the national popular vote doesn't determine who wins the race - it's about who wins the 270 points from electors in states across the country.
Perez named three states where a Biden victory would mean he should win the election - Wisconsin, Michigan and Pennsylvania. The Democrats won those states in the 2018 mid-terms, he points out.
Perez also said he believes that Texas - a traditionally Republican state - could go to Biden.
"We are playing offence. Trump is playing defence," he added.
You can watch the programme by clicking the play button at the top this page.
What happens when you put 13 Trump voters together with 12 Biden voters in a texting group? We’ll tell you throughout the night.
With only a few states projected at this time, emotions are running high.
“I am extremely anxious. Today could determine whether our democracy lives or dies.”
“I’m anxious and uncertain. We’re living through history and that’s always going to be a bit of a bumpy ride.”
Joe Biden is now projected to win Delaware, Maryland, Massachusetts and New Jersey, as well as the District of Columbia.
Donald Trump is projected to win Oklahoma.
Donald Trump is projected to win Kentucky.
The reliably Republican state has only voted Democratic in recent decades when a presidential candidate from the South has run, such as Jimmy Carter in 1976 and Bill Clinton in 1992 and 1996. Kentucky has eight electoral college votes.
Image source, Getty ImagesFox News is projecting that Senate majority leader Mitch McConnell will be re-elected in Kentucky.
First elected to the Senate in 1984, McConnell is Kentucky’s longest-serving senator. He's been in the headlines recently for leading Republican efforts to have Justice Amy Coney Barrett confirmed to the Supreme Court just weeks before election day.
A win for McConnell will not come as a surprise - Kentucky is a relatively safe state for Republicans. In 2016, Trump won it by a whopping 30 points.
Many more states are closing down voting for the night, and they together encompass some 238 electoral college points.
At 20:00ET (01:00GMT) polls close in: Alabama, Connecticut, Delaware, Florida, Illinois, Maine, Maryland, Massachusetts, Mississippi, Missouri, New Hampshire, New Jersey, Oklahoma, Pennsylvania, Rhode Island, and Tennessee.
Delaware, the small state Biden represented in the Senate for over three decades, will certainly back him.
Trump is all but certain to win Alabama, a state where Democratic Senator Doug Jones is fighting for his political life against a former US football coach.
Pennsylvania, with its 20 electoral college votes, is the state to watch. The "Keystone state" backed Trump in 2016. Both candidates have ties to the state. Biden was born in a mining town and lived there until the age of 10, while Trump attended university in Philadelphia.
When will we know who’s won Florida and why does it matter?
Florida is a big prize and it’s fiercely contested. It carries 29 electoral votes - a significant chunk of the 270 needed to win - and polls suggest a very tight race.
Donald Trump won the state by just over 1% in 2016.
Voting ends across the state in 10 minutes (20:00 ET, 01:00 GMT). Election officials began processing early votes before election day, so comprehensive results could be reported relatively quickly. They already have 80% of votes counted and it is neck-and-neck so far.
It’s a diverse state, with a large Hispanic population - although the Hispanic vote doesn’t overwhelmingly favour the Democrats as it does nationwide.
That’s because the large Cuban population tends to vote Republican. Many Cuban-Americans fled the Communist regime in their home country and can relate to Republican anti-socialist sentiment.
Older voters in the state could also be crucial – Florida is often referred to a "God’s waiting room" with more than 17% of the population being over 65. Mr Trump’s handling of the coronavirus outbreak could impact the senior vote with elderly people being most at risk.
It's also where Republican George W Bush secured the presidency in 2000 by just 537 votes, after a highly controversial recount.