Authorities in the states of Washington and Georgia are investigating a stash of suspicious envelopes sent to election offices this week that one state official deemed the incidents acts of "domestic terrorism."

In a statement on Thursday (November 9), Washington Secretary of State Steve Hobbs said that the envelopes were discovered to be containing "unknown powdery substances" - which the Spokane Police Department suspected to be fentanyl - when it was first encountered by election workers the day prior (Wednesday, November 8). The discovery prompted evacuations of the offices.

A similar incident was also reported in election offices in Seattle's King County, as well as in Skagit and Pierce counties.

Mystery Envelopes on East Coast

Meanwhile, on the US East Coast, Georgia Secretary of State Brad Raffensperger confirmed that election workers in Fulton County were sent a suspicious letter and that no other counties in the state appeared to have been targeted.

He also said the letter was intercepted before it arrived at the election office in Fulton county, and that no motive was determined so far.

"We're working with our state and federal partners to determine if any additional Georgia officials are being targeted," Raffensperger said in a statement obtained by ABC News. "Domestic terrorists will not trample on our right to free and fair elections."

A Fulton County spokesperson said no additional information was immediately available

A seal reading "Department of Justice Federal Bureau of Investigation" is displayed on the J. Edgar Hoover FBI building in Washington, DC, on August 9, 2022.STEFANI REYNOLDS/AFP via Getty Images

Justice Dept.: Investigations are Underway

The frequency of threats to election workers has become more frequent in recent years, which snowballed into the quitting of election workers in the aftermath of the 2020 presidential election.

"We are aware of the reports and the FBI and US Postal Inspection Service are investigating this matter," the Department of Justice said in a statement. "We have no further comment at this time."

FBI offices in Atlanta and Spokane have also confirmed they were collaborating with local law enforcement to investigate the incidents.

This is a developing story. Please follow HNGN for more updates.