Georgia Secretary of State Brad Raffensperger says a letter that contains fentanyl has been sent to an elections office in Fulton County in an act he is calling "domestic terrorism."

The development comes after four county election offices in Washington state were evacuated this week after workers there received letters with suspicious powders, according to the Associated Press, which reported that police in Kings and Spokane counties confirmed was fentanyl.

"We became aware of the situation that there is actually still an envelope that is traveling in the mail and headed towards Fulton County," Raffensperger told reporters Thursday. "It has been tested and it did have fentanyl in it."

"It is still in transit. It hasn’t arrived yet. They are trying to get that, intercept that before it gets here and we just don’t know where that will be," he continued. "But we have put and prepared our people here that could receive that mail on alert and given them the resources they need with Narcan." 

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Georgia Secretary of State Brad Raffensperger talks about fentanyl-laced letter

Georgia Secretary of State Brad Raffensperger speaks about the letter on Thursday, Nov. 9. (WAGA)

Raffensperger is calling the mailing of the letter "domestic terrorism and it needs to be condemned by anyone that holds elected office and anyone that wants to hold elected office anywhere in America." 

"I just want to really emphasize the seriousness of this. Some people like to call fentanyl a drug, but it’s actually poison. It will kill you. It will kick you very quickly, very easily. It’s very dangerous. We lost our son five and a half years ago due to a fentanyl overdose. We know how deadly this stuff is," he added.

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fentanyl powder

Fentanyl in powder form seized by law enforcement in Oregon. (Multnomah County Sheriff's Office )

The motive for the mailing of the fentanyl-laced letter to Georgia is unclear, according to Raffensperger. 

He suggested that the letter is linked to the ones that were delivered in Washington state.

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Raffensperger also said there will be a federal investigation into the incident.

Fox News' Samantha Daigle contributed to this report.