Russia-linked disinformation operations have falsely claimed officials in battleground states plan to fraudulently sway the outcome of the extraordinarily close US presidential election, authorities warned hours before Election Day.
Success in the seven swing states is key to winning the White House for rivals Kamala Harris and Donald Trump, and those states have previously been the focus of unsupported accusations of election fraud.
"Russia is the most active threat," the Office of the Director of National Intelligence (ODNI), the FBI and the Cybersecurity and Infrastructure Security Agency said Monday.
"These efforts risk inciting violence, including against election officials," they added, noting the efforts are expected to intensify through Election Day and in the following weeks.
It was the latest in a series of warnings from the ODNI about foreign actors -- notably Russia and Iran -- allegedly spreading disinformation or hacking the campaigns during this election.
Tehran and Moscow have both denied such allegations in the past.
The latest ODNI statement cited the example of a recent video that falsely depicted an interview with a person claiming election fraud in Arizona, which involved creating fake overseas ballots and changing voter rolls to favor Harris.
Arizona Secretary of State Adrian Fontes called the video and its claims "completely false, fake and fraudulent."
Authorities also said they expected Iranian-linked operations to try to stoke violence by spreading false content.
US officials warned in late October that Russia-linked operations were behind a viral video falsely showing mail-in ballots for Trump being destroyed in the swing state of Pennsylvania.
The video, which garnered millions of views on platforms such as X, purported to show a man sorting through mail-in ballots from the state's Bucks County and ripping up those cast for Trump.
The Bucks County Board of Elections branded the video as "fake," saying that the envelope and other materials depicted in the footage are "clearly not authentic materials" belonging to or distributed by them.
In September, the Microsoft Threat Analysis Center said Russian operatives are ramping up disinformation operations to malign Harris's campaign by disseminating conspiracy-laden videos.