Protesters have taken to the streets across the US to demand officials "count every vote" amid efforts by the Trump campaign to stop the democratic process.
Demonstrations were organised by voters on both sides in cities such as Detroit, Atlanta, Philadelphia and Minnesota.
While most were Biden supporters trying to resist claims by the Trump camp that counting should be stopped, Republican supporters made similar calls in states they have lost or are trailing behind.
In New York City, thousands of Democrats marched along Fifth Avenue, while people in cars and on bicycles rode past the White House with placards saying "This is a democracy - act like it".
On Wednesday night in Portland, Oregon, where Mr Biden is projected to win, 11 people were arrested and the National Guard was brought in to contain protesters in a repeat of recent clashes triggered by the death of George Floyd.
Tamera Cody, 22, voted for Donald Trump and was part of a small but dedicated group of his supporters outside the absentee ballot counting hall in Detroit on Thursday trading insults with Biden supporters across the street.
"I just feel like the election was really rigged," she told Sky News, after the Democrats claimed victory in Michigan.
"There are so many red counties - it doesn't make sense that it's gone to Biden. I don't feel like every vote is being counted. If every voter was being counted it wouldn't be this way. I didn't go to the polls for nothing.
"There was so many red counties on the map yesterday, yet we swing for Biden. It makes no sense."
Angelo Austin, 24, voted for Mr Biden and went to protest outside the Detroit counting centre when he heard Trump supporters were there contesting the result.
He told Sky News: "What motivated me to come down here today is this - the same city they are protesting in is the same city that was built on the backs of Black labourers.
"I lost my job due to COVID-19. These people [Trump supporters] are able to go home and eat while we are worrying about how to pay the gas bill."
He added: "There is no talking to these people about the way I feel. My ancestors worked for free for 200 years to build the economy we have today."
Before the election, Donald Trump implied the surge in mail-in ballots was being used by the Biden campaign to "steal the election".
And with several states yet to declare their results two days on, Mr Trump has filed lawsuits in Michigan, Pennsylvania, Georgia, Nevada and Wisconsin - alleging electoral fraud is taking place and the counts should stop altogether.
While there is no evidence for this, Mr Trump has tweeted: "All of the recent Biden claimed states will be legally challenged by us for voter fraud and state election fraud."
Other posts, including "STOP THE COUNT!" and "STOP THE FRAUD", have been removed by Twitter, which claims they are "disputed and might be misleading about an election or other civic process".
Voting had to be paused in Philadelphia amid lawsuit claims from members of the Trump campaign, including his lawyer Rudy Giuliani, that some ballots have come from people who are dead or live outside the state.
In Georgia, where the result is still undecided, Sky News spoke to Tom Biklind, a 52-year-old pilot originally from Norway who has been in the US for 30 years. He voted for Donald Trump, but is still concerned that legal votes will not be counted.
"I'm disappointed they are still counting the votes," he said.
"For several reasons: certain deadlines are not being followed, people who are dead are still voting - the news media reported that from Michigan. I don't think that's a single incident. Every election in this country dead people vote.
"I also wanted to make sure that all the legal votes are counted. If everything is legal and kosher there shouldn't be a problem. It should be supervised by both parties not someone who is 'so-called independent'."
He added that he wants to see a recount if the result is tight.
"We don't mind losing an election if it's fair. We're adults. I would have to respect it if Biden wins now but if it's within 1% for example there should be a recount," he said.
In Nevada, where Mr Biden is ahead so far, a Trump news conference claimed a voter called Jille Stokke was unable to vote when she turned up at the polls in Las Vegas.
They called for all voting to be halted, but a local registrar later confirmed he had spoken with the woman and she had already voted once and was trying to vote again.
At a news conference near his home in Delaware on Thursday, Mr Biden urged his supporters to be patient and said "all votes must be counted" to cheers from supporters.