WASHINGTON (NEWSnet/AP) — Authorities on Thursday were trying to determine who sent suspicious letters, including some filled with fentanyl or other substances, to local election offices.

The attack appears to have targeted multiple states.

Officials in at least three states, Georgia, Oregon and Washington, reported concern about letters targeting election workers.

Among the offices that appeared to be targeted was Fulton County in Georgia,  which includes Atlanta and is the largest voting jurisdiction. Authorities were working to intercept the letter.

Secretary of State Brad Raffensperger said officials are sending the overdose-reversal drug naloxone to the office as a precaution.

“This is domestic terrorism, and it needs to be condemned by anyone that holds elected office and anyone that wants to hold elective office anywhere in America,” Raffensperger said.

Authorities in Lane County, Oregon, which includes the University of Oregon, were investigating a piece of mail that arrived at the local election office Wednesday. No one who came in contact with it had experienced any negative health effects, said Devon Ashbridge, spokeswoman for the Lane County Elections Office in Eugene.

The incident prompted officials to close the office and delayed an afternoon pickup of ballots.

On Wednesday, authorities in Washington state said four county election offices had to be evacuated as election workers were processing ballots cast in Tuesday’s election, delaying vote-counting.

Election offices in Seattle’s King County and in Skagit, Spokane and Pierce counties received envelopes containing powder. Local law enforcement officials said the substances in King and Spokane counties field-tested positive for fentanyl. In at least one other case, the substance was baking soda.

Tacoma Police spokesperson William Muse told The Seattle Times that a message inside the envelope received by Pierce County election workers said “something to the effect of stopping the election.” No specific candidate was identified, Muse said.

Elections offices in King and Okanogan counties also received suspicious envelopes while processing ballots during the August primary, and the letter sent to King County tested positive for traces of fentanyl.

Washington Secretary of State Steve Hobbs called the incidents in his state “acts of terrorism to threaten our elections.”

A spokesperson for U.S. Department of Justice said FBI and the postal authorities are investigating, but had no further comment.

In the advisory Thursday, Georgia state officials warned counties to take precautions when handling mail.

Raffensperger said the state alerted all 159 of its counties of the possible threat Wednesday, but believes only Fulton County is being targeted.

Fulton County Commission Chairman Robb Pitts, speaking at a news conference Thursday with Raffensperger, said the county’s election workers had been under threat since at least two were singled out following the 2020 presidential election.

“There’s people out there who want to do harm to our workers and want to disrupt, interrupt, the flow of democracy and free, open and transparent elections, and we’re prepared for it” Pitts said.

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