The statement said that Moscow is using a “range of measures” to “primarily denigrate” Mr Biden, the presumptive Democratic presidential nominee, who is seen as part of the “anti-Russia establishment”.
But it also says that Beijing prefers that Mr Trump “does not win reelection” and sees him as “unpredictable”, while Tehran is opposing the president due to his hardline “pressure campaign” towards it.
The remarks were issued by William Evanina, director of the US National Counterintelligence and Security Centre, who is helping lead the American intelligence efforts against election meddling.
The 900-word statement, headlined ‘Election threat update for the American people’, spells out in detail how the three countries are attempting to influence the election.
The intervention is a sign of how the US intelligence agencies are attempting to get ahead of election interference after criticism that in the 2016 campaign the public was left in the dark about the extent of Russia’s meddling.
It also comes on the back of mounting criticism from leading Democratic political figures claiming there has been a lack of briefings about what is really being done by America’s foreign adversaries during this race.
“Our election should be our own. Foreign efforts to influence or interfere with our elections are a direct threat to the fabric of our democracy,” Mr Evanina said.
Warning that foreign states will use “covert and overt influence measures” to sway US voters, Mr Evanina singled out three countries in particular – Russia, China and Iran.
“We assess that Russia is using a range of measures to primarily denigrate former vice president Biden and what it sees as an anti-Russia ‘establishment’,” he said of the Kremlin.
Mr Evanina said the criticism was consistent with that which was targeted at Mr Biden when he was Barack Obama’s vice president and supported Ukraine against Russia-backed fighters.
He called out Andriy Derkach, a pro-Russia parliamentarian in Ukraine, for “spreading claims about corruption” about Mr Biden, picking him as an example of the anti-Biden campaign from Russia.
“Some Kremlin-linked actors are also seeking to boost President Trump’s candidacy on social media and Russian television,” Mr Evanina said.
On China, Mr Evanina said: “We assess that China prefers that President Trump – whom Beijing sees as unpredictable – does not win reelection.”
He said that Beijing has been expanding its influence to shape policy in the US ahead of the November 3 election and has harshly criticised recent Trump administration moves on Tik Tok, Hong Kong and 5G networks.
“Beijing recognises that all of these efforts might affect the presidential race,” Mr Evanina said.
On Iran, Mr Evanina said: “We assess that Iran seeks to undermine US democratic institutions, President Trump, and to divide the country in advance of the 2020 elections.
“Iran’s efforts along these lines probably will focus on on-line influence, such as spreading disinformation on social media and recirculating anti-US content.
“Tehran’s motivation to conduct such activities is, in part, driven by a perception that President Trump’s reelection would result in a continuation of U.S. pressure on Iran in an effort to foment regime change.”
The information given is only what can be shared in an “unclassified setting”, Mr Evanina noted at one point, which could mean there is more covert meddling activity from the countries.
The decision to go public with the claims shows the degree to which the US administration is concerned by the threat posed by foreign meddling in the election, now less than 100 days away.
Mr Evanina said that as well as influencing voters foreign powers could seek to “compromise our election infrastructure” by interfering in the voting process, such as stealing sensitive data, though he said such moves would be “difficult” to do at scale.