Two government security breaches in 2006 were just the tip of the iceberg, leaving sensitive information wide open to espionage and cybercriminals, according to a leading member of the House Committee on Homeland Security.

James Langevin, D-R.I., speaking before the House Homeland Security Committee's cybersecurity panel on Thursday afternoon, said he was "disappointed and troubled" about the state of the U.S. government's cybersecurity policies. The two computer break-ins at the Department of State and the Department of Commerce last summer are very likely deeper and more insidious than even the government has reported.

And Langevin contends that there are more security breaches that the public simply doesn't hear about.

"Let me be clear about the threat to our federal systems: I believe the infiltration by foreign nationals of federal government networks is one of the most critical issues confronting our nation," said Langevin, who is chairman of the Subcommittee on Emerging Threats, Cybersecurity, and Science and Technology. "The acquisition of our government's information by outsiders undermines our strength as a nation. ... This is a most critical issue that we cannot afford to ignore any longer."

Langevin, who is also is a member of the House Committee on Homeland Security, led Thursday's panel discussion on cybersecurity.

David E. Jarrell, manager of the Commerce Department's Critical Infrastructure Protection Program, testified before the committee, describing how a locked-down computer led IT investigators to discover that hackers had infiltrated the network via Chinese networks. The security breach was discovered on July 13, but investigators could not say when the hackers gained entry or exactly where they went inside the network. While Jarrell testified that there was no evidence that data "was lost" during the incident, he could not say if it had been copied and transferred outside of the government network.

The breach was in the Bureau of Industry and Security section of Commerce. That section deals with what technologies -- generally nuclear or technologies of a national security nature -- that are too sensitive to be exported to other countries.