The Washington Post is reporting new details on the NSA's massive phone-record collection efforts, with leaked documents that indicate the program caches five billion call records each day, tracking the locations of hundreds of millions of mobile devices. Previous Snowden leaks had detailed the NSA's extensive access to consumer phone records, but it was unclear before now whether that metadata included the location of each phone. The latest documents confirm that it does, as part of a much larger location-tracking effort.

One collection manager told the post the NSA was collecting "vast volumes" of location data from around the world, primarily by tapping into the cables that connect mobile networks globally, but insisted the collection is "incidental" rather than intentional and is focused on phones outside of the United States. Still, the result is unprecedented access to the movements of citizens on a global scale. "Analysts can find cellphones anywhere in the world, retrace their movements and expose hidden relationships among individuals using them," the article states. As metadata, the location data is not considered to be covered by the Fourth Amendment.

The piece also goes into the details of how specific phones are flagged for scrutiny within the system. Efforts toward anonymity like using burner phones only attract the NSA's curiosity, singling users out for further surveillance. The report also says the NSA recently upgraded their infrastructure to accommodate the swelling quantity of data, which is now said to be larger than 27 terabytes in sum.