Hoax bomb threats, many appearing to originate from Russian email domains, have been directed at polling locations in three US battleground states on US presidential election day, the FBI says.

“None of the threats have been determined to be credible thus far,” the FBI said on Tuesday (local time), adding that election integrity was among its highest priorities.

The states targeted by the hoax bomb threats were Georgia, Michigan and Wisconsin.

At least two polling sites in Georgia were briefly evacuated on Tuesday. Those two locations in Fulton County reopened after about half an hour, officials said, and the county was seeking a court order to extend their voting hours past the 7pm (local time) deadline.

There were more threats throughout the day.

“We planned heavily for the incident of a bomb threat being called. And it’s a good thing we did, because that’s the only thing that happened today was 32 bomb threats at different polling locations,” local police chief W. Wade Yates said.

Republican Georgia Secretary of State Brad Raffensperger blamed Russian interference for the election day bomb hoaxes.

“They’re up to mischief, it seems. They don’t want us to have a smooth, fair and accurate election, and if they can get us to fight among ourselves, they can count that as a victory,” Raffensperger said.

The Russian embassy in Washington did not immediately respond to a request for comment.

Reuters could not immediately determine how many hoax bomb threats there were in Michigan and Wisconsin.

Wisconsin Elections Commission head Ann Jacobs said fake bomb threats were sent to two polling locations in the state capital of Madison, but did not disrupt voting.

An FBI official said that Georgia alone received more than two dozen, most of them in Fulton County. It encompasses much of Atlanta, which is a Democratic stronghold.

A senior official in Raffensperger’s office, speaking on the condition of anonymity to speak freely, said the Georgia bomb hoaxes were sent from email addresses that had been used by Russians trying to interfere in previous US elections.

The threats were sent to US media and the two polling locations, the official said.

“It’s a likelihood it’s Russia,” the official said.

Democratic Vice-President Kamala Harris and Republican former president Donald Trump are locked in a tight race to win the White House.

The phoney bomb threats mark the latest in a string of examples of alleged interference by the Russians in the 2024 election.

On November 1, US intelligence officials warned that Russian actors manufactured a video that falsely depicted Haitians illegally casting ballots in Georgia.

Intelligence officials also found the Russians created a separate phoney video that falsely accused someone associated with the Harris presidential ticket of taking a bribe from an entertainer.

US intelligence officials have also accused Russia of interfering in previous US presidential elections, especially the 2016 race that Trump won against Democratic candidate Hillary Clinton.

-with AAP