The U.S. Department of Justice is gathering mobile phone data from “innocent Americans” using technology which can track criminal suspects using aeroplanes, a Wall Street Journal report has claimed.

According to sources familiar with the supposed spying programme, U.S. authorities are using devices known as ‘dirtboxes’ on aeroplanes, which mimic mobile phone towers, to access data from phones on the ground.

The dirtboxes act as network operators which provide signal to devices on land, through which the U.S. Marshals Service has reportedly been able to obtain the phone’s registration and identification data. This airborne method supposedly cuts the amount of time it takes for the information to be collected from mobile operators, as well as allowing for a greater volume of data to be collected with increased precision.

The discovered technology is also capable of intercepting other signals in order to capture data from text or photo messages, the WSJ has suggested.

However, authorities have attempted to avoid potential harm by adjusting the software to make sure the technology does not affect calls to emergency services, a source familiar with the programme said.

dirtboxes

Dirtboxes are supposedly used regularly in military flight and, in a similar vein to other surveillance programmes made public recently, gather data like a ‘dragnet’ pulling information from innocent civilians without warrant.

“It’s inexcusable and it’s likely—to the extent judges are authorising it—[that] they have no idea of the scale of it,” said Christopher Soghoian, chief technologist at the American Civil Liberties Union.

Although the sources reported that information collected from ‘innocent’ people is ‘let go’ immediately, the storage and disposal methods for this type of data could not be confirmed.

As seen with the Snowden revelations, this discovery is expected to create divided response; some believing authorities are right to do everything they can to protect their citizens by tracking criminal activity; others arguing that governments should not tread over an individual’s right to privacy in the process.

“Maybe it’s worth violating privacy of hundreds of people to catch a suspect, but is it worth thousands or tens of thousands or hundreds of thousands of peoples’ privacy?” Soghoian added.