The United States Justice Department has formally charged members of the Chinese military with stealing trade secrets from American cyber targets, marking the first time in history that the United States has charged a state actor in a criminal cyber espionage case.

Attorney General Eric Holder, who announced the charges in a press conference on Monday morning, said five officers of the Chinese People's Liberation Army stole large amounts of information from U.S. companies in Western Pennsylvania and elsewhere by hacking into their networks and maintaining prolonged unauthorized access there. "The range of trade secrets and other sensitive business information stolen in this case is significant and demands an aggressive response," he said.

Holder said that the stolen information "would have been particularly beneficial to Chinese companies at the time they were stolen," and added that sensitive, internal communications were compromised that would have allowed an adversary of the United States or competitor to gain "insight into the strategy and vulnerabilities of the American entity."

Victims of the alleged cyber espionage include Westinghouse Electric, Alcoa, Allegheny Technologies Incorporated, U.S. Steel, the United Steelworkers Union, and SolarWorld. Those companies represent nuclear power, metals, and solar products industries.

Holder emphasized that the charges against the Chinese military should serve as an example to other would-be cyber criminals. "The indictment makes clear that state actors who engage in economic espionage, even over the Internet from faraway offices in Shanghai, will be exposed for their criminal conduct and sought for apprehension and prosecution in an American court of law," he said.