Russia has sought to “amplify” concerns over the integrity of U.S. elections by promoting allegations that mail-in voting will lead to widespread fraud, according to an intelligence bulletin obtained by ABC News, again echoing a frequent and unfounded complaint raised by President Donald Trump.

Analysts with the Department of Homeland Security’s intelligence branch issued the warning on Thursday to federal and state law enforcement partners after finding with “high confidence” that “Russian malign influence actors” have targeted the absentee voting process “by spreading disinformation” since at least March.

“Russian state media and proxy websites in mid-August 2020 criticized the integrity of expanded and universal vote-by-mail, claiming ineligible voters could receive ballots due to out-of-date voter rolls, leaving a vast amount of ballots unaccounted for and vulnerable to tampering,” the bulletin notes.

“These websites also alleged that vote-by-mail processes would overburden the U.S. Postal Service and local boards of election,” it continues, “delaying vote tabulation and creating more opportunities for fraud and error.”

President Trump has long sought to undermine public confidence in the upcoming election with baseless warnings that mail-in-voting could lead to widespread voter fraud. With the ongoing coronavirus pandemic expected to keep many voters from casting their ballots in-person, more Americans than ever are expected to vote absentee.

John Cohen, the former undersecretary for intelligence at DHS under President Barack Obama, said the parallel messages emanating from both the Trump campaign and Russian malign actors is “highly disturbing.”

“This most recent DHS intelligence report along with other recent reporting by intelligence and law enforcement entities should put to rest any doubts that Russia is spreading conspiracy theories and lies in an effort to influence the outcome of the 2020 election by undermining confidence in the election process and influence voter opinion,” said Cohen, who is also an ABC News contributor.

On Wednesday, ABC News first reported that senior DHS officials withheld a July bulletin from distribution that found that Russia would continue raising questions about the mental health of Biden to impact the 2020 election – a line of attack the president, 74, and his reelection campaign have also used against the former vice president, who will turn 78 shortly after Election Day.

The July bulletin, titled "Russia Likely to Denigrate Health of US Candidates to Influence 2020 Election," also mentioned Iranian and Chinese schemes to criticize President Donald Trump.

Andrew Bates, a Biden campaign spokesperson, said Thursday, "This is the second time in two days it has been revealed that Donald Trump and the Russian government are pushing the same malicious smear about the 2020 election." He accused Trump and Russia of being "aligned in assaulting" democracy.

Tim Murtaugh, a Trump campaign spokesperson, said in response to ABC News' original report, "We don't need or want any foreign interference."

"President Trump will beat Joe Biden fair and square," he said.

In a statement to ABC News, a DHS spokesperson confirmed that the July product was "delayed," explaining that it "lacked the necessary context and evidence for broader dissemination."

After ABC News published its report, acting Homeland Security Secretary Chad Wolf also acknowledged that the bulletin was withheld, calling it “a very poorly written report” during an appearance on Fox News.

Congressional Democrats have since pledged to investigate the episode as part of the House Intelligence Committee’s ongoing inquiry into the Department of Homeland Security's intelligence agency's activities during protests in Portland, Ore.