The claims echo repeated unfounded predictions by Trump and his campaign that fraud would occur, casting doubt on the results and laying the groundwork for legal challenges.
Challenging the results soon after polls closed, Trump tweeted that: "We are up BIG, but they are trying to STEAL the Election."
A screenshot of a tweet taken on November 4, 2020
AFP examines several other claims of fraud that are circulating online.
Also Read: Did A Donald Trump Supporter Block A Polling Site On Election Day?
Biden surge in Michigan
The number of reported votes for Biden, the Democratic candidate, jumped by more than 138,000 on Wednesday morning, drawing online accusations of foul play.
"So while everyone was asleep and after everyone went home, Democrats in Michigan magically found a trove of 138,339 votes, and all 138,339 of those 'votes' magically went to Biden? That doesn't look suspicious at all," one Twitter user wrote.
A screenshot of a tweet taken on November 4, 2020
But it was caused by human error when a zero was added as votes were counted. The mistake was quickly fixed after state officials noticed it, but a real-time report by an independent analyst fed claims of fraud online.
Caroline Wilson, county clerk for the central Michigan county of Shiawassee, told AFP. "I added an extra zero accidentally," thereby reporting 153,710 votes for Biden instead of 15,371.
"The minute it was discovered, it was corrected, probably within 20 minutes, so I'm amazed how fast this spread," Wilson said.
When the figure was lowered by the correction, 138,339 votes were removed from Biden's total tally without any changes to Trump's numbers.
Sharpie pen fraud in Arizona
It was claimed that Arizona voters were pushed to use Sharpie pens on their ballots in a bid to make them illegible and keep votes for Trump from being counted.
"The poll workers were taking the pens from voters and making them use Sharpies. Sharpies bleed through. All of the votes marked with Sharpies couldn't be read," said one Facebook post.
A screenshot of a Facebook post taken on November 4, 2020
It included a video in which a man said: "People are coming here to vote for Donald Trump, and those votes are all getting invalidated."
But officials -- including Arizona Secretary of State Katie Hobbs -- said using a Sharpie would not invalidate ballots, while voters also had the option of bringing their own pens.
"IMPORTANT: If you voted a regular ballot in-person, your ballot will be counted, no matter what kind of pen you used (even a Sharpie)!" Hobbs wrote on Twitter -- an assessment echoed by the election department of the state's most populous county.
Also Read: No Violation Occurred At Pennsylvania Polling Station As Falsely Claimed
Too many voters in Wisconsin?
Social media posts claimed that the number of people who cast ballots in Wisconsin exceeded the total number of registered voters.
"WISCONSIN REPORTING 101+% VOTER TURNOUT! 3,170,206 Votes Counted. 3,129,000 Registered Voters," an Instagram post said.
A screenshot of an Instagram post taken on November 4, 2020
But it and other posts used an inaccurate number for registered voters. According to the Wisconsin Elections Commission, the figure stood at 3,684,726 as of November 1 -- and it may have risen since.
Reid Magney, Public Information Officer of the Wisconsin Elections Commission, warned of numbers mentioned in online reports and that could be several days older.
"Wisconsin has election day registration… Typically hundreds of thousands of people register to vote on election day across the state," he said.