The FBI is urging election officials nationwide to be on guard against cyber attackers.

FOX's Rachel Sutherland reports from Washington:

The warning comes after election systems were compromised in Arizona and Illinois... FBI Director James Comey was asked about the breaches at a symposium here in Washington. He wouldn't comment on the specifics but said:

(Comey) "Those kinds of things are something we take very very seriously and work very hard to understand so we can equip the rest of our government with options on how to deal with it."

Senate Democratic Leader Harry Reid is worried Russia may try to impact the Presidential election and he's sent a letter to Comey calling on the FBI to investigate.

In Washington, Rachel Sutherland, FOX News.

Follow Rachel Sutherland on Twitter: @SutherlandFOX