Election security: Officials say 2024 election saw only 'minor' disruptive activities

Additional non-credible bomb threats were sent to polling locations in the Atlanta area, according to Georgia Secretary of State Brad Raffensperger, as a dozen counties remain open late due to threat-related evacuations earlier in the day.

"I know that in Atlanta, they just got a whole bunch of bomb threats coming through," Raffensperger said at a press briefing Tuesday evening. "All the precincts are staying open and they're just sending dogs around to sweep it to make sure they're safe."

"Best we can tell these would probably be coming from the same source," he added, referring to his earlier claim that Russia was behind the threats.

Raffensperger said 12 counties across the state are remaining open late due to threats to polling places: six in Dekalb, five in Fulton and one in Gwinnett.

Three additional counties will be open late due to "normal causes," he said.

A poll observer identified the error that resulted in Milwaukee officials' decision to rerun approximately 31,000 absentee ballots earlier today.

Milwaukee's top election official said that the city's election results will likely be reported in the "early morning hours" after an error at a central processing location forced a retabulation of those ballots.

Milwaukee Election Commission Director Paulina Gutierrez said the error was identified by a poll observer -- a member of the public who watches election officials for the sake of transparency.

The Trump campaign criticized Milwaukee election officials for the error.

"This is an unacceptable example of incompetent election administration in a key swing state: voters deserve better and we are unambiguously calling on Milwaukee's officials to do their jobs and count ballots quickly and effectively," RNC Chairman Michael Whatley and Co-Chair Lara Trump said in a statement.

"It's a human error," Gutierrez said. "That is the point of central county elections, is that it's transparent, and the observers brought it to our attention."

A top Cybersecurity and Infrastructure Security official said there is "no evidence" that there is cheating in Philadelphia and Detroit as former President Donald Trump has claimed.

"We have been in very close contact with state and local election officials across the country, and we see no data or reporting to support these claims," Cait Conley, the senior adviser to the CISA Director and head of elections said on a call with reporters.

Nationally, Conley said officials "are not currently tracking any significant incidents with national level impacts to election infrastructure security."

Additionally, she said officials expect to see Russian disinformation actors piggyback off the hoax bomb threats that were sent to Arizona, Georgia, Michigan and Wisconsin by the Russians.

"We should not be surprised if we do," she said in response to a question about Russian actors using the hoax bomb threats. "Our adversaries are specifically intent on leveraging opportunities to spin narratives to undermine confidence."

-ABC News' Luke Barr

There are "residual issues" including long lines at the polls in Apache County, Arizona, after the machines that print ballots "did not work as planned" Tuesday morning, state officials said.

The countywide issue was fixed earlier in the day and most sites in the county are "up and running well but as we understand at this moment, there are still some residual issues out in Apache County," Arizona Secretary of State Adrian Fontes said. "We're doing our best to work with county election officials there to see if we can resolve any of the remaining problems."

Rita Vaughan, the elections director for Apache County, told ABC News that "all polling places have remained open and voting has continued all day for registered voters who want to cast their ballots."

-ABC News' Laura Romero