Video report by ITV News International Affairs Editor Rageh Omaar
Americans are turning out in what is projected to be record-breaking numbers to vote in the US presidential election that some believe will lead to further division to the country facing the worse public health crisis in a century.
Americans braved long queues and strict Covid safety measures to make their choice between incumbent president Donald Trump and his Democratic rival, former vice president, Joe Biden.
Those voting in person join the record 102 million Americans who voted early.
Mr Trump struck an upbeat note as polls open, predicting the night would be a "tremendous success" for his administration and he would return to Washington DC with a bigger majority than in 2016.
Speaking to reporters at the Republican National Committee offices in Virginia, Mr Trump claimed victory would bring unity America which, he said, had been derailed by what he described as "the China virus".
The Covid-19 pandemic has claimed 231,000 lives in the US, but Mr Trump insisted his party had done "an incredible job" in managing the virus.
"We closed up the greatest economy in the history of the world for any country, not just for our country, and we are now opening it up," he said in a speech, surrounded by his campaign team.
"We saved more than two million lives and did an incredible job with therapeutics, and with, I think maybe cures, because frankly, some of this stuff is so good."
He said he had not written a concession or victory speech, but admitted "losing is never easy, not for me" before describing his campaign rallies as events "no one has ever seen before in the history of the world".
Mr Biden began election day at a church in Delaware, with his wife Jill and two grandchildren where the family visited their late son Beau Biden's grave in the church cemetery.
The former vice president then flew to childhood home and church in his native Scranton in Pennsylvania. His running mate, Sen. Kamala Harris, was visiting Detroit, a heavily black city in battleground Michigan. This election is set against a backdrop of increasingly divisive race relations following a summer of protests sparked by the death of George Floyd – an unarmed black man - at the hands of a white police officer that catapulted the fury over racial injustice in the US back into focus.
After a campaign marked by rancor and fear, voters on both sides will likely be eager to move on but unrest around the result might delay the country doing that.
Already Washington's shops and businesses are boarded-up and residents are deeply nervous. While new security fencing rings the White House.
Multiple law enforcement agencies are on standby for riots and disturbances as the results roll in.
"I'm ashamed to be an American" - this tearful Joe Biden supporter is one of many people in Florida casting their ballots in this key state. #election2020
Emotions are running high in the key battleground state of Florida. ITV News spoke to one Joe Biden supporter who said she was "ashamed to be an American" after four years of Trump's presidency.
But another voter said the incumbent president had "done a lot of good things" during his tenure and cast his ballot for the Republican candidate.
Florida plays an enormously important role in determining who is handed the keys to the White House.
The state has supported the overall winner of the US Election for the last six year US elections; twice it was kingmaker, determining the overall victor. Florida is a must win state for the incumbent president Mr Trump. No Republican has won the election without claiming the state in the last 100 years. If Donald Trump does with this key battleground state, Mr Biden will be under immense pressure to present college votes in the other battleground states; in Pennsylvania, Michigan and Wisconsin - each of which Mr Trump won in 2016.
Polls will close at different times across the US at the end of election day, usually on the hour. Alaska will be the final state to close polling booths on election day.
As soon as this happens, a state can be "called" by the US news networks for one candidate or the other once they are confident who is going to win there.
A rush of projections are likely when polls close in more than a dozen safe states.
Given that a few states, including Texas, had already exceeded their total 2016 vote count, experts have been predicting record turnout this year.
Many people used their postal vote instead, despite President Trump's unfounded claims around the system's legitimacy.
The record-setting early vote - and legal wranglings over how it will be counted - have drawn unsupported allegations of fraud from the president, who has refused to guarantee he will accept the result.
While usually a result could be expected by the early hours of Wednesday, UK time, with so many variables this time around it's unclear at which point we'll know who has won.
On their final full day on the campaign trail on Monday, Mr Trump and Mr Biden spoke sharply over the mechanics of the vote itself with respective visits to the most fiercely contested battleground, Pennsylvania.
The Republican president threatened legal action to block the counting of ballots received after Election Day.
While Mr Biden told voters that the very fabric of the nation was at stake and offered his own election as the firmest rebuke possible to a president who he said had spent "four years dividing us at every turn."
Analysis from ITV News Washington Correspondent Robert Moore
We may - or may not - know the result by Wednesday morning. But the division won't be healed overnight. If he loses, the president will have one final decision to make. Does he accept defeat and walk off the stage with a degree of dignity, reluctantly embracing the political norms that he despises? Or does he go down with all guns blazing, saying he has been cheated, and alleging that the election has been stolen by Democrats?
Watch Trump vs Biden: The Results on Tuesday 3rd November from 11pm on ITV and itv.com/news.