United States spy services reportedly conducted 231 "offensive cyber operations" in 2011, mostly targeting Iran, Russia, China and North Korea.
The revelation in the Washington Post is based on a classified intelligence budget provided to the paper by fugitive leaker Edward Snowden, as well as on interviews with former US officials.
The newspaper is also reporting that, under a $US652 million project code-named "GENIE", US specialists hack foreign computer networks to secretly put them under American control.
This involves placing covert implants in computers, routers and firewalls, it says.
By the end of the year, the newspaper says the project is forecast to control at least 85,000 malware plug-ins in machines around the globe.
The Washington Post says US intelligence services make routine use of government-constructed malware around the globe that "differs little in function from the 'advanced persistent threats' that US officials attribute to China."
However, while an unnamed National Security Agency spokesman confirmed to the newspaper that the Defense Department does engage in computer network exploitation, the paper also quoted him as saying that, unlike China, the department does not engage in economic espionage in any domain.
