Next to nuclear bombs or other “weapons of mass destruction”, the global threat that concerns U.S. Federal Bureau of Investigation (FBI) most is cyber terrorism.

At a homeland security conference in New York City yesterday, FBI Cyber Division Assistant Director Shawn Henry told delegates, “Other than a nuclear device or some other type of destructive weapon, the threat to our infrastructure, the threat to our intelligence, the threat to our computer network is the most critical threat we face.”

Michael Balboni, NY state Deputy Secretary of Public Security, described cyber terrorism as “a huge threat” which could compromise many critical infrastructure systems, such as power distribution and municipal water supply as well as communications, banking and business systems.

Speakers at the New York conference agreed that the U.S. has not yet been targeted for the kind of serious attacks they fear, but there’s proof that what used to be called “hacking” and was performed by individual notoriety seekers has now been embraced by foreign governments with the intent to spy on their untrusted neighbours and, in some cases, to attack their digital infrastructures.

Russia, China and various terrorist groups were spotlighted as being among the leaders in developing “cyber weapons”. Conference delegates urged U.S. authorities to catch up in developing the means to defend the country against such potentially crippling attacks.

And that’s all aside from the cyber crime epidemic which is expected to cost the world’s economy at least as much as the current economic crisis and continues to grow.