Chinese spies have much better access to US government and defense industry computer networks, according to a congressional advisory panel report.
The US-China Economic and Security Review Commission told Congress that there was evidence to suggest Chinese state involvement in such activities.
Apparently, Beijing has begun to broaden its national security concerns beyond a potential clash across the Taiwan Strait and issues around its periphery.
It is now conducting espionage against the United States, focused on obtaining data and know-how to help military modernization and economic development, the Commission added.
The Commission was concerned that the Chinese had placed many of its capabilities for computer network operations within elements of the People's Liberation Army.
"China's peacetime computer exploitation efforts are primarily focused on intelligence collection against US targets and Chinese dissident groups abroad," it said.
The committee did not say how it had found out about the attacks or their location. It seemed to depend heavily on a report by the contractor Northrop Grumman.