FBI Chief Responds to Concern Over Cyber Threats to US Election System

The FBI has responded to recent concerns about the American election system being targeted for cyber-attacks as the presidential elections approach, saying they take the threat "very, very seriously" and are working to "equip the rest of our government with options."

"We take very seriously any effort by any actor," FBI Director James Comey told government and private-industry experts attending the Symantec Government Symposium in Washington, "to influence the conduct of affairs in our country, whether that's an election or something else."

His comments come one day after news surfaced about FBI warnings to the states that hackers had successfully infiltrated one state board of election and targeted another.

Three days ago, Senate Democratic leader, Sen. Harry Reid, D-Nevada, sent a letter to Comey, expressing concern that "the threat of the Russian government tampering in our presidential election is more extensive that widely known and may include the intent to falsify official election results."

In late June, an "unknown actor scanned a state's Board of Election website for vulnerabilities" and, after identifying a security gap, exploited the vulnerability to conduct a "data exfiltration," the FBI said in a recent "flash" bulletin.

Earlier this month, hackers used the same vulnerability in an "attempted intrusion activities into another state's Board of Election system," the FBI said.

The bulletin did not say who may be behind the cyber attacks, or where they may be located. But many suspect Russian hackers could be to blame.

In the recent cyber-attacks, voter-related information was stolen from the Illinois election system, and hackers tried to access Arizona's system, according to Yahoo News, which first reported on the bulletin.

"The prospect of a hostile government actively seeking to undermine our free and fair elections represents one of the gravest threats to our democracy since the Cold War," Reid wrote in his Aug. 27 letter to Comey, adding that the FBI should "investigate this matter thoroughly."

Reid is not alone in his concerns over potential election day cyber vulnerabilities.

Three weeks ago, the ranking member of the Senate Homeland Security Committee called on the federal government to examine its efforts to protect election systems and voting machines in the United States against similar attacks.

"Election security is critical, and a cyberattack by foreign actors on our election systems could compromise the integrity of our voting process," wrote Sen. Tom Carper, D-Delaware, in a letter to the Department of Homeland Security.

For months, the FBI has been investigating what appear to be coordinated cyber-attacks on Democratic organizations, with the hacking of the Democratic National Committee being the most damaging so far.

Not only did the hack apparently allow cyber operatives to steal opposition research on Republican nominee Donald Trump, but many suspect it led to the theft of internal messages that showed efforts by DNC officials to undermine Democratic presidential candidate Bernie Sanders during the primary season.

After those damaging emails were publicly released by WikiLeaks, Florida Rep. Debbie Wasserman Schultz stepped down as DNC chairwoman.

Many suspect Russian hackers are also to blame for these cyber-assault on Democratic organizations.

At the symposium in Washington today, Comey said state-sponsored hackers from places like Russia, China, Iran and North Korea "are getting much more sophisticated [and] much more aggressive" in their online activities.

ABC News' Ali Rogin and Geneva Sands contributed to this report.