Iranian influence specialists are behind threatening emails sent to voters in Alaska and Florida, U.S. officials said on Wednesday evening and suggested that more such interference could be in store from Russia.

Director of National Intelligence John Ratcliffe said the U.S. intelligence community believes Iranian and Russian operatives obtained voter-record information, which enabled Iran to target some people with intimidating emails based on party registration about how they'd better vote for President Trump "or else."

The senders posed as members of the white supremacist Proud Boys and claimed they had voter data that revealed for whom their targets voted — but that was a false flag, the U.S. says.

Ratcliffe sought to reassure Americans about the integrity of their votes and the processes by which elections are run.

"These actions are desperate attempts by desperate adversaries," Ratcliffe said, but pledged confidence in American elections and said, "You can be confident your votes are secured."

Russian influence specialists don't appear to have used their voter data in a similar scheme, Ratcliffe said, but they may.

His warning followed months of similar cautions by U.S. officials about the threats of interference posed by foreign actors, which have never abated since the historic spike of Russian "active measures" in the 2016 election on behalf of President Trump.

Since then, however, Ratcliffe and FBI Director Christopher Wray said, U.S. officials have worked to toughen America's election infrastructure and have become more vigilant about election security — work they said has paid off with the awareness demonstrated Wednesday night.