The head of the nation’s cyber defense agency said Monday that a technical hack could not change the final outcome of the presidential race, but Americans are facing a “firestorm” of misinformation leading up to Election Day.

Jen Easterly, director of the Cybersecurity and Infrastructure Security Agency, said there has been an “unprecedented amount” of disinformation this election cycle, including content marketed by foreign adversaries aimed at undermining American democracy and turning citizens against each other.

“We cannot allow our foreign adversaries to have a vote in our democracy,” Easterly told reporters on a media call.

A malicious actor could not materially impact the outcome of a presidential election by tampering with the voting system, thanks to layers of safeguards such as physical access controls, pre-election equipment testing and post-election audits, the agency said.

Meanwhile, the National Association of Secretaries of State and the National Association of State Election Directors said Monday that their members and colleagues at the local level have devoted “a lot of time, energy and resources” to protecting the election.

“Planning for tomorrow’s elections began four years ago, and the electoral community is ready,” according to a statement from the groups.

On the eve of a contentious presidential election, officials are trying to shore up public confidence during an election cycle marked by a maelstrom of misinformation.

US government officials tried increase transparency and announced disinformation from foreign powers in an attempt to reduce its impact, a reversal from their approach eight years ago when Russian influence efforts tried to boost Donald Trump’s 2016 presidential bid.

Meanwhile, Trump, the Republican nominee, has repeatedly tried to undermine confidence in the electoral process with baseless claims of voter fraud, a tactic he has used in the past.

Asked about Trump’s false claims, Easterly praised free speech and avoided addressing his specific claims, but said it was “very irresponsible” for people in positions of influence to spread inaccurate information about the US election.

US intelligence officials have spent the last few weeks before the election debunking specific instances of disinformation.

Over the weekend, the FBI reported that a video claiming the agency had busted three groups committing voter fraud was fake, as was a second video linked to second-in-command Douglas Emhoff.

“These videos are not authentic, they are not from the FBI, and the content they depict is false,” according to a statement from the agency on social media.

“Attempts to deceive the public with false content about FBI operations undermine our democratic process and seek to erode trust in the election system,” the FBI said.

In another example, the intelligence community assessed that Russian actors produced and amplified a video falsely showing a person plucking ballots in the swing state of Pennsylvania.

And intelligence community officials reported that Russian actors were behind a fake video showing people “pretending to be from Haiti and voting illegally in several Georgia counties.”

The review was based on information available to the intelligence community and “prior activities of other Russian influence actors,” according to the joint statement by CISA, the FBI and the Office of the Director of National Intelligence.

Georgia Secretary of State Brad Raffensperger, in a statement last week, said a video purported to show a multi-identity Haitian immigrant from Georgia who claimed to have voted multiple times.

Raffensperger described the video as fake. “It is probably foreign interference trying to sow discord and chaos on the eve of the 2024 presidential election,” he said.