WASHINGTON | Tue Nov 16, 2010 2:23pm EST

WASHINGTON (Reuters) – The United States faces a major threat in the future from cyber technologies that will require civil-military coordination to shield networks from attack, Defense Secretary Robert Gates said on Tuesday.

“I think there is a huge future threat. And there is a considerable current threat,” Gates told The Wall Street Journal CEO Council. “And that’s just the reality that we all face.”

The U.S. Defense Department estimates that over 100 foreign intelligence organizations have attempted to break into U.S. networks. Every year, hackers also steal enough data from U.S. government agencies, businesses and universities to fill the U.S. Library of Congress many times over, officials say.

The Pentagon’s biggest suppliers — including Lockheed Martin Corp, Boeing Co and Northrop Grumman Corp — are investing in the growing market for cyber technology, estimated at up to $140 billion a year worldwide.

Gates said the U.S. military had made considerable progress protecting its own sites and was working with its private-sector partners “to bring them under that umbrella.”

But how to allow Pentagon know-how to be applied to protecting domestic infrastructure can be tricky for legal reasons, including fear of violating civil liberties.

“The key is the only defense that the United States has against nation-states and other potential threats in the cyber-world is the National Security Agency,” Gates said, referring to the super-secretive Defense Department arm that shields national security information and networks, and intercepts foreign communications.

“You cannot replicate the National Security Agency for domestic affairs. There isn’t enough money. There isn’t enough time. And there isn’t enough human talent.”

Last month, President Barack Obama’s administration announced steps to allow greater cooperation between the NSA and the Department of Homeland Security. That includes stationing the DHS’ privacy, civil liberties and legal personnel at the NSA.

“So you have the domestic security agency, DHS, being able to reach into NSA in a real-time way to get the kind of protection we need,” Gates said.

“And my hope is that over time that will lead to better protections for both ‘.gov’ and ‘.com.'”

(Reporting by Phil Stewart; Editing by Eric Beech