The US has charged five men who it described as "military hackers" with hacking into US corporations to steal secrets that could be useful to Chinese companies, in the first case of its kind.
A grand jury in the Western District of Pennsylvania indicted the five men for computer hacking, economic espionage and other offences directed at six US organisations in the nuclear power, metals and solar products industries.
The indictment alleges that the defendants conspired to hack into US organisations to steal information that would be useful to their competitors in China, including state-owned enterprises.
"This is a case alleging economic espionage by members of the Chinese military and represents the first ever charges against a state actor for this type of hacking," US Attorney General Eric Holder said.
"The range of trade secrets and other sensitive business information stolen in this case is significant and demands an aggressive response. Success in the global market place should be based solely on a company's ability to innovate and compete, not on a sponsor government's ability to spy and steal business secrets."
The US Justice Department said the five men were officers in Unit 61398 of the Third Department of the Chinese People's Liberation Army.
The US Justice department said the hacking took place between 2006 and this year and organisations targeted included Westinghouse Electric Co, US subsidiaries of SolarWorld, US Steel, Allegheny Technologies Incorporated (ATI), the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union (USW) and Alcoa Inc.
FBI director James B. Comey said: "For too long, the Chinese government has blatantly sought to use cyber espionage to obtain economic advantage for its state-owned industries."
The Department of Justice noted that an indictment is merely an accusation and a defendant is presumed innocent unless proven guilty in a court of law. The Chinese embassy in Washington could not immediately be reached for comment.