The United States has indicted five members of the Chinese military on allegations they stole US secrets to help state-run companies.
The US Department of Justice has accused the five individuals of engaging in "economic espionage".
It is the first time that the US has publicly accused China of cyber-spying.
The Department of Justice said the hackers had targeted US companies in the nuclear power, metals and solar products industries, and is accusing them of stealing information to help Chinese competitors.
US officials said the companies targeted include Alcoa Inc, United States Steel Corp, Allegheny Technologies Inc, Westinghouse Electric Co and US subsidiaries of SolarWorld AG.
The charges were announced this morning by US Attorney General Eric Holder.