Washington (dpa) - Iran and Russia have taken action to influence public opinion relating to the November US presidential election, the national intelligence director John Ratcliffe said Wednesday.

"We have confirmed that some voter registration information has been obtained by Iran, and separately by Russia," Ratcliffe said.

"This data can be used by foreign actors to attempt to communicate false information to registered voters that they hope will cause confusion, sow chaos, and undermine your confidence in American democracy."

Iran has been sending false emails designed to intimidate voters and incite social unrest, Ratcliffe said.

The Director of the Federal Bureau of Investigations (FBI), Christopher Wray, added that US election infrastructure is still resilient and that US officials would not tolerate foreign election interference.

"We’re not going to let our guard down," he said.

Officials did not take questions from journalists following the press conference.

US intelligence officials previously determined that Russia interfered in the 2016 US presidential election in a bid to boost President Donald Trump.

Ratcliffe did not mention Russia's attempts to interfere in the 2020 election, but said that Iran is working to undermine Trump.