Homeland Security Secretary Jeh Johnson says terror threats against the U.S. are evolving.

FOX's Rachel Sutherland reports from Washington:

The nation's intelligence leaders are growing more concerned about homegrown terror attacks, than threats from abroad.

Secretary Jeh Johnson said would-be terrorists are finding inspiration online:

(Johnson) "The prospect of the next terrorist-inspired attack on the homeland is the thing that keeps us up at night."

Johnson also talked about the upcoming election, telling lawmakers 18 states have come forward asking for help securing their voting systems from cyber attacks.

In Washington, Rachel Sutherland, FOX News.

Follow Rachel Sutherland on Twitter: @SutherlandFOX