The NSA inadvertently gathers the location records of "tens of millions of Americans who travel abroad" annually, along with the billions of other records it collects by tapping into worldwide mobile network cables, the newspaper reported on Wednesday.
Such data means the NSA can track the movements of almost any cellphone around the world, and map the relationships of the cellphone user. The Post said a powerful analytic computer program called CO-TRAVELER crunches the data of billions of unsuspecting people, building patterns of relationships between them by where their phones go. That can reveal a previously unknown terrorist suspect, in guilt by cellphone-location association, for instance.
As the NSA doesn't know which part of the data it might need, the agency keeps up to 27 terabytes, or more than double the text content of the Library of Congress' print collection, the Post said. A 2012 internal NSA document said the volumes of data from the location program were "outpacing our ability to ingest, process and store" it, the newspaper said.
The program is detailed in documents given to the newspaper by former NSA systems analyst Edward Snowden. The Post also quotes unidentified NSA officials, saying they spoke with the permission of their agency.
Shawn Turner, a spokesman for the Office of the Director of National Intelligence, declined to comment on the report.
Rights activists say those measures fall short of protecting US privacy.
"The scale of foreign surveillance has become so vast, the amount of information about Americans 'incidentally' captured may itself be approaching mass surveillance levels,'" said Elizabeth Goitein of the Brennan Center for Justice's Liberty and National Security Program.
"The government should be targeting its surveillance at those suspected of wrongdoing, not assembling massive associational databases that by their very nature record the movements of a huge number of innocent people," said Catherine Crump, a staff attorney for the American Civil Liberties Union.
NTJ/NJF