Asked how he would characterize the hacking of state election systems and whether it is a threat that requires immediate action from the government, Comey said the Federal Bureau of Investigation works "very hard to understand" that kind of activity "so that we can equip the rest of our government with options for how to deal with it".
The FBI is warning state officials to boost their election security in light of evidence that hackers targeted related data systems in two states.
Two attempts to breach state voter records-one in IL, one in Arizona-have been traced back to Russian hackers, according to a report from The New York Times.
The FBI suspects the two intrusions in Arizona and IL were linked.
The FBI alert, first reported by Yahoo News, did not mention Russian Federation. The FBI warning - contained in a "flash" alert from the FBI's Cyber Division, a copy of which was obtained by Yahoo News - comes amid heightened concerns among USA intelligence officials about the possibility of cyberintrusions, potentially by Russian state-sponsored hackers, aimed at disrupting the November elections. IL officials similarly suspended their voter registration system after discovering a breach in July.
In Arizona hackers unsuccessfully tried to breach the voter registration system using malicious software, reports said.
The FBI's August 18 warning also came just days after Homeland Security Secretary Jeh Johnson hosted a call with secretaries of state and other state election officials to talk about cybersecurity and election infrastructure. However, officials concluded the system was not successfully compromised.
Election officials say they've since implemented measures to reinforce the system.
"In addition, California elections officials are required to conduct a manual tally of 1 percent of the precincts as part of the official canvass of election results as a safeguard to ensure votes were accurately read and tallied".
Hackers apparently connected to Russian Federation staged a series of cyber-attacks against United States media outlets including the New York Times, reports said earlier this month. The Democratic National Committee was hacked last month, with embarrassing emails showing coordination between the DNC and the Hillary Clinton campaign being released publicly.
Experts said they believed two Russian intelligence agencies to be responsible.
Last week Senate minority leader Harry Reid asked the FBI to investigate evidence suggesting Russia may be trying to manipulate voting results in November, expressing concern about a "direct connection" between Republican candidate Donald Trump's campaign and the Russian government.
"The prospect of a hostile government actively seeking to undermine our free and fair elections", he wrote, "represents one of the gravest threats to our democracy since the Cold War".