US intelligence officials say there is no evidence of foreign efforts to meddle with mail-in voting, refuting President Donald Trump’s claims.
The report comes amid an ongoing row over the US Postal Service, which is tasked with handling mail-in ballots for the November presidential election.
A vast number of Americans are expected to vote by post due to the pandemic.
Mr Trump has for months alleged, without evidence, that large-scale mail voting will lead to voter fraud.
On Wednesday, a senior national intelligence official told reporters: “We have no information or intelligence that any nation-state threat actor is engaging in any kind of activity to undermine any part of the mail-in vote or ballots.”
It contradicts Mr Trump’s remarks that voting by mail – which he himself has done – is susceptible to foreign interference.
In the wake of confirmed Russian interference during the 2016 election, US authorities have been seeking to safeguard systems ahead of the 3 November poll.
Election security officials earlier this month confirmed that the Kremlin was working against Democratic presidential nominee Joe Biden, while China would prefer a Mr Biden win. Iran may also attempt to interfere with US institutions.
Mr Trump has dismissed the notion that the Russians are seeking to boost his campaign.
A cybersecurity official on Wednesday’s call noted that targeting voting machines is “in the playbook” for governments like Russia but that no such effort has successfully affected American’s ability to vote.
“We saw it in 2016, we know it’s an option now,” the official said. “We continue to receive reporting from state and local election officials of scanning and probing of election infrastructure as a whole.”
Officials also said that more than 90% of votes during the 2020 election should have an auditable record.
Deputy Attorney General Jeffrey Rosen, speaking at another event on Wednesday, echoed the same, saying the US has “yet to see any activity intended to prevent voting or to change votes”.
He noted that Russia, China and Iran were still attempting to interfere.
But the president has claimed that expanded mail-in voting would lead to “the most corrupt election” in US history.
In an interview with the Washington Examiner on Wednesday, Mr Trump said he was more concerned about “unsolicited ballots” being sent and issues with local officials counting votes, than the post office itself.
“The problem is when they dump all these [ballots] in front of a few people who are counting them, and they’re going to count them wrong,” he said. “The post office is not to blame.”
What else is going on in the postal row?
Hawaii, New Jersey and New York states have sued the Trump administration over changes it made to the US Postal Service (USPS) ahead of the election.
The suit claims Mr Trump sought to “undermine mail-in voting efforts”.
Democrats allege that the Trump-appointed agency chief tried to deliberately “sabotage” the election with a series of recent reforms.
Postmaster General Louis DeJoy – a top Republican donor – has dismissed the accusations, telling senators earlier this month that all ballots will arrive on time and reforms would only be enacted after the election.
He was responsible for changes including cuts to overtime pay and the removal of mail boxes.