Since 2010, the NSA has been using "metadata" -- the GPS location of a call, travel documents, email recipients, Facebook profile information and other things -- to fill out dossiers of American citizens, The New York Times said Saturday.
Former NSA contractor Edward Snowden revealed this year the agency was tracking all domestic calls as a means to investigate terrorism suspects -- regardless of whether they are linked to foreign terror suspects.
In the past, the tactics were known to be used against foreign terror suspects. In November 2010, the NSA began applying the procedures to Americans -- and did so without the approval of the secret Foreign Intelligence Surveillance Court.
Now, the Times said, it's clear the NSA, using sophisticated information tracking software, is attaching more than just phone logs to people.
An NSA spokeswoman said the agency doesn't investigate Americans unless there's a viable link between them and suspected foreigners.
"All data queries must include a foreign intelligence justification, period," the spokeswoman said. "All of NSA's work has a foreign intelligence purpose. Our activities are centered on counterterrorism, counterproliferation and cybersecurity."
The metadata collection process, though highly controversial, is not illegal. The practice stems from a Supreme Court ruling that Americans have no expectation of privacy for phone numbers they call, making phone records fair game for law enforcement to access.