The falsehoods promoted on sites including the Elon Musk-owned X and Meta's Threads range from unfounded claims about fraudulent vote tallies in key swing states to allegations that Trump "cheated" to win against his Democratic rival Kamala Harris.
Left-leaning social media users also spread the unfounded theory that Musk -- the world's richest man and a vociferous Trump backer –- used his Starlink satellite internet company to rig the election by manipulating the vote count, AFP's fact-checkers reported.
"What we're seeing now is an uptick in election fraud claims from the left, particularly in the days following Election Day -- and these narratives are being amplified by bot networks," Dan Brahmy, chief executive of the disinformation security company Cyabra, told AFP.
"It's a reminder that disinformation and exploitation tactics don't belong to one political ideology -- they're weaponized across the board to influence public perception."
- 'Shared vulnerability' -
The Democratic leadership has not questioned the election's outcome, with both Biden and Harris conceding the loss and deeming the November 5 election free and fair.
But just hours after the election, X was flooded with over 30,000 mentions of the hashtag "Do Not Concede Kamala" alongside the words "rigged," "fraud," or "stolen," according to the misinformation watchdog NewsGuard.
Some pro-Harris influencers implored her to "demand a recount" in posts that garnered millions of views.
Cyabra said it uncovered a "highly coordinated disinformation campaign" on X promoting the false notion that the election was "stolen," a narrative that initially gained traction through a network of fake profiles and was later amplified by real influencers.
Some users deployed a deliberate tactic, misspelling the vice president's name in their hashtags as "Kamila" to evade detection while amassing engagement.
The misspelling tactic, Cyabra said, was used to circumvent platform moderation as it "reduces the likelihood of automated content takedowns."
"The recent shift in election fraud claims reveals a deeper, shared vulnerability" on both sides of the political divide," Brahmy said.
"Narratives that may start as fringe beliefs can, under the right conditions, permeate mainstream discourse, regardless of political alignment."
- 'Information warfare' -
Left-leaning social media users picked up what researchers call the misinformation baton from Trump's right-wing supporters, who vigorously pushed unfounded claims of voter fraud since the Republican's 2020 election defeat.
This time around, right-wing claims flooded social media platforms right up to Election Day, but began tapering off as Trump's decisive victory took shape.
"You could call it a role-reversal," said Sam Howard, NewsGuard's political editor.
"As Trump's win became more apparent, there were fewer fraud claims from the right. But now there is a disbelief on the left that Harris's defeat was legitimate."
Such claims have spread unchecked as many platforms have gutted trust and safety teams and scaled back content moderation efforts once used to tame misinformation.
"Right-wing election deniers were largely placated by the results of the election, but it's not so much that disinformation is no longer a problem or that it has suddenly, miraculously, disappeared," Nora Benavidez, senior counsel at the nonprofit watchdog Free Press, told AFP.
"Information warfare is only becoming more pernicious and, when given time to take root, serves as a critical building block to advance authoritarianism and bigotry," she added.
