The National Security Agency (NSA) has access on the same tools that enable Internet advertisers to track consumers, using "cookies" and location data, according to a Washington Post report. According to the agency's internal presentation slides, provided by former NSA contractor Edward Snowden, when companies follow consumers on the Internet to better serve them advertising, the technique opens the door for similar tracking by the NSA. The slides also suggest that the agency is using these tracking techniques to help identify targets for offensive hacking operations.

According to the documents, the NSA and its British counterpart, GCHQ, are using "cookies" that advertising networks place on computers to identify people browsing the Internet. The intelligence agencies have found particular use for a part of a Google-specific tracking mechanism known as the "PREF" cookie. These cookies contain numeric codes that enable Web sites to uniquely identify a person's browser.

Google'd PREF cookie appears anytime someone's browser makes a connection to any of the company's Web properties or services. That cookie contains a code that allows Google to uniquely track users to "personalize ads" and measure how they use other Google products.

It is not clear how the NSA obtains Google PREF cookies or whether the company cooperates in these programs.

The NSA declined to comment on the report.

Google chief executive Larry Page joined the leaders of other technology companies earlier this week in calling for an end to bulk collection of user data and for new limits on court-approved surveillance requests.

Another slide indicates that the NSA is collecting location data transmitted by mobile apps to support ad-targeting efforts in bulk. This allows NSA to map Internet addresses to physical locations more precisely.

Even when GPS is disabled on a smartphone, most devices silently determine their location in the background using signals from Wi-Fi networks or cellular towers.