Misleading allegations, rumours and outright lies about voting and fraud are flooding online spaces in unprecedented numbers in advance of the US election.

Hundreds of incidents involving purported voting irregularities are being collected and spread by individuals, as well as both independent and Republican-affiliated groups. A small number of posts are also coming from Democrats.

The whirlwind of claims spreading online poses a challenge to election officials who are having to debunk rumours and reassure voters, while preparing to administer election day on November 5.

In nearly every case, the posts support the Trump campaign’s false claim that the former president won the 2020 election and suggestions that he will potentially be cheated out of victory again on November 5.

When asked whether he will accept the 2024 election result, Donald Trump said during the presidential debate in September that he would if it was a “fair and legal and good election”.

A majority of Americans – 70% – expect him to reject the result if he loses, according to a CNN/SSRS poll released Monday.

Just this week, Donald Trump himself claimed widespread fraud in a key swing state.

“Pennsylvania is cheating, and getting caught, at large scale levels rarely seen before,” Donald Trump posted on his Truth Social network. “REPORT CHEATING TO AUTHORITIES. Law Enforcement must act, NOW!”

The allegation followed officials in three Pennsylvania counties saying they were working with local law enforcement to investigate some voter registration applications for potential fraud.

While Donald Trump and allies seized on the announcements, the state’s top election official, Republican Al Schmidt, has urged caution and warned voters to be aware of “half-truths” and disinformation circulating on social media.

Hundreds of allegations of election fraud online, on social networks and on message boards and in chat groups. Some of these posts have been viewed millions of times each.

The posts have implied it’s easy for non-citizens to vote, made false claims about voting machines and sowed distrust in the ballot-counting process.

One video claimed to show recently-arrived Haitians voting in Georgia.

Meanwhile in Northhampton County, Pennsylvania, a video was posted on X showing a man dropping off a container of ballots at a courthouse, alleging suspicious activity. It turned out he was a postal worker delivering mail-in ballots, but the video was seen more than five million times.