London: The US and UK intelligence agencies use Google`s proprietary cookie technology to track suspects, according to the latest revelations from leaked NSA documents.
The NSA and GCHQ`s use `GooglePrefIDs - files containing a numeric code placed on computers to help the search firm remember users, the BBC reports.
The two agencies piggybacked the files to `home in` on targets already under suspicion.
According to the report, the cookie surveillance technique is the latest in a series of alleged spy agency activities.
Google said it uses `preferences` cookies to enhance people`s use of the internet.
The company explained that these cookies allow its websites to remember information that changes the way the site behaves or look.
According to the report, a document published by the Washington Post suggests the spy agencies also track other types of cookies, but does not specify which.
The NSA added that it was `within its lawful mission to collect foreign intelligence to protect the United States,` the report added.
