Washington, United States | With AFP information

Iranian intelligence was responsible for a recent campaign of emails sent to intimidate Florida voters, the FBI announced Wednesday night, adding that Russia was also working to influence the election.

The emails, which were directed to Democratic voters in Florida to switch to the Republican Party, purported to come from the Proud Boys, the right-wing group of Trump supporters that became a flashpoint during the first presidential debate.

Russian and Iran have both obtained US voter information and taken actions to influence public opinion ahead of the November 3 election, Director of National Intelligence John Ratcliffe announced Wednesday.

Ratcliffe said Iran specifically had sent "spoofed" emails to Americans "designed to intimidate voters, incite social unrest, and damage President Trump."

He said Iran had also distributed a video that implies that people could send in fraudulent ballots, including from outside the United States.

Ratcliffe said both Iran and Russia seek to use information obtained "to communicate false information to registered voters that they hope will cause confusion, sow chaos, and undermine confidence in American democracy."

"These actions are desperate attempts by desperate adversaries," he said.

The announcement came after registered Democratic voters reported receiving personally addressed emails in the name of the Proud Boys armed militia group.

"You will vote for Trump on election day or we will come after you," the emails said.

Ratcliffe, with FBI Director Christopher Wray beside him, did not explain how the Russians and Iranians had obtained the voter information, or how the Russians might be using it. 

Wray stressed that US election systems remained safe and "resilient".

"Rest assured that we are prepared for the possibility of actions by those hostile to democracy," Ratcliffe said.