The hackers are said to have sent unwanted emails to individuals who worked for Biden's campaign, containing "stolen, non-public material" from the former president's campaign organization.
None of Biden's campaign staff responded to the emails, according to the authorities.
Kamala Harris' campaign organization, which took over after Biden handed over his candidacy, calls the Iranian influence attempt an "unwelcome and unacceptable malicious activity" and states that those who received the emails regarded them as spam or phishing.
In August, the authorities stated that Iran was behind the cyberattack on the Trump campaign. The hackers are also said to have attempted to share information with several American media outlets.
Iran hacked into my campaign. I don't know what they found, I'd like to find out. Can't have been too exciting, said Trump at a campaign meeting in the state of New York on Wednesday evening, according to Politico.
According to the FBI, the attack is part of a broader strategy from Tehran, aimed at influencing American politics and undermining trust in democratic institutions.
Iran's UN delegation denies involvement and stated on Wednesday that it lacks motivation to interfere in the American presidential election.
