Supporters of US President Joe Biden listen to him speak during a campaign event at Renaissance High School in Detroit, Michigan, US, 12 July 2024; Credit: Reuters/Elizabeth Frantz/File Photo

(Reuters) - Iranian hackers sent emails containing stolen material from Republican former President Donald Trump's campaign to people involved in Democratic President Joe Biden's then re-election campaign, part of an alleged broader effort by Tehran to influence the US election, US agencies said on Wednesday 18 September 2024.

"Furthermore, Iranian malicious cyber actors have continued their efforts since June to send stolen, non-public material associated with former President Trump’s campaign to US media organisations," the FBI, Cybersecurity and Infrastructure Security Agency, and Office of the Director of National Intelligence said in a joint statement.

"This malicious cyber activity is the latest example of Iran's multi-pronged approach [...] to stoke discord and undermine confidence in our electoral process," the agencies said.

They added that there is currently no information indicating those recipients replied. They did not provide further details on the nature of the stolen material.

In August 2024, the United States accused Iran of launching cyber operations against the campaigns of both US presidential candidates and targeting the American public with influence operations aimed at fanning political discord.

Iran has denied interfering in US affairs. On Wednesday, its permanent mission to the United Nations in New York said the latest US allegations were "fundamentally unfounded, and wholly inadmissible". It added: "Iran neither has any motive nor intent to interfere in the US election."

Malicious cyber actors sent unsolicited emails to individuals in Biden's campaign in late June and early July 2024 that contained a text excerpt from stolen material from the Republican presidential candidate's campaign, the agencies said.

Biden dropped out of the presidential race on 21 July 2024 and was replaced by Vice President Kamala Harris as the Democratic candidate. Polls show Trump and Harris are in a tight race.

In a statement, the Trump campaign said Harris and Biden should disclose whether they used the hacked material "to hurt" Trump. The former president later said in a rally on Wednesday night that Iran hacked into his campaign to help Democrats, calling it foreign election interference.

"We're not aware of any material being sent directly to the campaign," a Harris campaign spokesperson said after the statement by US agencies. "A few individuals were targeted on their personal emails with what looked like a spam or phishing attempt."

Tehran also says Washington has interfered in its affairs over decades ranging from a 1953 coup of a prime minister to the 2020 killing of Iranian military commander Qassem Soleimani.