Foreign hackers recently infiltrated two state election systems, according to an alert from the FBI's Cyber Division.

The FBI document does not name the two states, but Yahoo News reports that they are Arizona and Illinois.

The hack in Illinois was said to be more severe. After the cyber attack was detected last month, the Illinois voter registration system had to be shut down for 10 days. Hackers reportedly accessed personal information on as many as 200,000 Illinois voters.

The identity of the hackers has not been determined. Eight different IP addresses were responsible for the two attacks. One IP address was connected to both attacks, according to Yahoo News.

"The FBI is requesting that states contact their Board of Elections and determine if any similar activity to their logs, both inbound and outbound, has been detected," the FBI's bulletin states. "Attempts should not be made to touch or ping the IP addresses directly."

Earlier this month, Homeland Security Secretary Jeh Johnson spoke with state election officials on ways to better safeguard their voting systems from hackers. States were reportedly offered assistance from federal officials to have their systems scanned for vulnerabilities.

UPDATE (4:08 p.m.): Ken Menzel, general counsel for the Illinois State Board of Elections, said it appears that personal information from less than 200,000 voters may have been accessed in the recent hack into the state's voter registration system.

That being said, the elections board said it "may never know the exact number of affected voters" because of "the ambiguous nature of the attack."

The elections board is, however, "very confident nothing was added, deleted or altered" due to the hack, Menzel told the Chicago Tribune.

The breach of Illinois' voter registration system reportedly started June 23 and was stopped after being detected July 12.

Voting history information and voter signatures were not obtained in the attack, according to the Illinois elections board.