15/01/2014 08:44 GMT | Updated 23/01/2014 18:56 GMT

NSA Hacked Offline Computers With Tiny USB Radios, Claims New York Times

We already know that the US National Security Agency (NSA) has been spying on virtually every computer connected to the internet - to say nothing of apparently similar efforts by our own authorities.

What we didn't know was that NSA agencies were able to hack computers that weren't even connected to the web.

According to documents leaked by Edward Snowden and reported by the New York Times, the NSA was able to put software on around 100,000 computers around the world to carry out surveillance and prepare the ground for cyberattacks.

But the report also said that the agency had been able to gain entry to devices that were not otherwise online, thanks to the use of relatively simple, but secret technology.

The paper said that tiny circuit boards and USB cards were placed in computers by agents as early as 2008, and then transmitted data via radio waves picked up by American forces.

In some cases the radio transmissions were able to be tracked by "briefcase-size relay stations" set up miles away from the computer, the Times reported. It said that these briefcase machines can hack data and send back messages to machines up to eight miles away.

"The radio frequency technology has helped solve one of the biggest problems facing American intelligence agencies for years: getting into computers that adversaries, and some American partners, have tried to make impervious to spying or cyberattack," the NYT said.

"In most cases, the radio frequency hardware must be physically inserted by a spy, a manufacturer or an unwitting user."

The program, known as Quantum, targeted systems in the Chinese military, as well as Europe, Russia, Mexico, Saudi Arabia and Pakistan among others. But the Times said there was no evidence the NSA had used the radio tech outside of the US.