Republican congressional candidate Karen Handel and several of her neighbors received suspicious packages Thursday containing an unknown substance, in an incident being investigated by the FBI and other agencies, Fox News confirms.

“The FBI is responding along with Roswell Police Department and Fire to a suspicious white powder with letters,” Special Agent Stephen Emmett in the FBI Atlanta Field Office told Fox News. “The situation is at several residences in Roswell, including Karen Handel’s house.”

Handel, who lives in a neighborhood in Roswell, Ga., and will face off against Democrat Jon Ossoff in a special election next week for Georgia’s 6th District seat, confirmed the report.

“This afternoon, we had some suspicious packages delivered to our house and to our neighbors,” Handel said in a statement. “The packages contained threatening letters and a suspicious substance.”

According to Handel, police were “quickly notified” and her street was blocked off.

“We will continue to coordinate with law enforcement as necessary,” Handel said.

The FBI also told Fox News that the FOX 5 Atlanta affiliate in Atlanta, Ga., was in receipt of an unknown white substance.

“We have yet to make a connection between the two incidents,” Emmett told Fox News.

The affiliate received a package with a white powdery substance inside a clear plastic envelope. The package also contained a document with anti-Donald Trump and anti-Karen Handel language, according to FOX 5 Atlanta.

According to FOX 5 Atlanta, the package and its contents were secured in a containment box after being opened. A hazardous materials team was brought in to investigate. The powdery substance has not yet been identified.

According to FOX 5 Atlanta, the document in the package threatened violence, and also read in part: "America's terrorist soldiers are raping and killing innocent Muslims by the thousands. Republicans are literally ushering in the apocalypse by ignoring the impending climate disaster."

The package was postmarked in Greenville, South Carolina. Law enforcement officials said the suspicious packages delivered to Karen Handel's Roswell neighborhood were also mailed from Greenville, according to FOX 5 Atlanta.

Mike McClain, vice president of news at FOX 5 Atlanta, tweeted a photo of DeKalb authorities in hazmat suits testing the suspicious powder.

Lisa Holland with the Roswell Police Department told WSB-TV in Atlanta that they do not know the nature of the substance at this time.

“We take all these threats seriously. We’ve been having a lot of issues with political signs over the past months,” Holland said. “This has just been a situation over the campaign on both sides.”

The incident comes a day after House Majority Whip Steve Scalise, R-La., and four others were injured in a shooting at a congressional baseball practice outside Washington.

Handel and Ossoff are competing for the seat left by President Trump’s Secretary of Health and Human Services Tom Price.

Ossoff said his campaign has also received threats.

“Our campaign has received a number of threats, some of which have intensified in recent days," Ossoff said in a statement. "We have reported them to local police as well as taken prudent precautions.