The assessment showed that Moscow considers Biden's politics to be part of the "anti-Russia" establishment, and that as vice president, Biden drew frequent criticism from Russia for his role in forming hard-line USA policy on Ukraine while vocally opposing Russian President Vladimir Putin.
"Foreign efforts to influence or interfere with our elections are a direct threat to the fabric of our democracy", he said. The Russian hackers also probed state IT systems across the country.
Evanina's statement, three months before the election, comes amid criticism from House Speaker Nancy Pelosi and other congressional Democrats that the intelligence community has been withholding from the public specific intelligence information about the threat of foreign interference in American politics.
Senate Intelligence Committee Acting Chair Marco Rubio (R-Fla.) and Vice Chair Mark Warner (D-Va.) on Friday said this statement "highlights some of the serious and ongoing threats to our election".
Google revealed earlier this summer, for instance, that Chinese and Iranian-linked hackers were observed trying to get into the email accounts of campaign staffers for both Trump and Biden. "Some Kremlin-linked actors are also seeking to boost President Trump's candidacy on social media and Russian television", Evanina said.
China prefers Biden over President Donald Trump because of concerns over the Trump administration's criticisms of Beijing's handling of COVID-19, and its efforts to derail China's aggression in the South China Sea.
Evanina also ascribed activities to Russia that were reminiscent of its interference in 2016, when Russia trolls bankrolled by an ally of Russian President Vladimir Putin used social media platforms to flame political divisions in the United States and spread false information.
The top counterintelligence official in the US government warned Friday of ongoing interference and influence efforts by China, Russia and Iran.
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These nations "have a preference for who wins the election", it added.
The US statement called out by name Andriy Derkach, a pro-Russia Ukrainian lawmaker who has been active in levelling unsubstantiated corruption allegations against Biden and his son concerning Burisma, the Ukrainian natural gas company on whose board Hunter Biden Saturday.
Evanina said Iran is seeking to undermine Trump and divide the country before the vote.
"Tehran's motivation to conduct such activities is, in part, driven by a perception that President Trump's re-election would result in a continuation of U.S. pressure on Iran in an effort to foment regime change".
"Iran's efforts along these lines probably will focus on online influence, such as spreading disinformation on social media and recirculating anti-US content", Evanina wrote.
Today's statement comes after one issued in July, when Evanina provided an overview of foreign threats to the USA 2020 presidential election, saying that foreign adversaries were seeking to "compromise the private communications of US political campaigns, candidates and other political targets".
Christopher Krebs, head of the US Cybersecurity and Infrastructure Security Agency, also released a statement warning of Moscow interference.
In response Iran fired missiles at a USA military base in Iraq though they didn't cause any fatalities.