FBI Director Robert Mueller called cyber threats the top future threat facing America in testimony this week before the Senate Intelligence Committee, InformationWeek reports. The broad range of online threats, both from state and non-state actors, highlights a complex threat to key institutions of the government, economy, and media.

"I do not think today it [cyber terrorism] is necessarily [the] number one threat, but it will be tomorrow," Mueller said. "Counterterrorism — stopping terrorist attacks — with the FBI is the present number one priority. But down the road, the cyber threat, which cuts across all [FBI] programs, will be the number one threat to the country."

Director of National Intelligence James Clapper underscored the complexity of threat. Internet attacks are difficult to predict and act on, he said, and "many intrusions into U.S. networks are not being detected." Joining major state actors China and Russia, Iran has also broadened its capabilities and hyped up its willingness to act on attacks. In addition, hacker groups like Anonymous, which brings together thousands of members of the public to act on its own 'campaigns,' have struck key sectors of the economy.

Congress is taking this threat seriously after dragging its feet for years, with the House dealing with cyber security legislation this week and the Senate considering a more comprehensive bill later this month.

Israel provides a model for how cyber attacks occur and how they can be countered. It is fighting an online war with Arab hackers, who have struck financial and governmental websites, as well as released Israeli credit card data.