In their globe-spanning surveillance for terrorism suspects and other targets, the US National Security Agency and its British counterpart GCHQ have been trying to exploit mobile phone technology, a report in The New York Times said.
When a smartphone owner opens Angry Birds, the popular game, and starts slinging birds at chortling green pigs, spies could be lurking in the background to snatch intimate details like a user's "political alignment" and sexual orientation, the report said.
The NSA and Britain's Government Communications Headquarters were working together on how to collect and store data from dozens of smartphone apps by 2007, the report said, citing documents provided by Snowden to The New York Times, The Guardian and ProPublica.
Since then, the agencies have traded recipes for grabbing location and planning data when a target uses Google Maps, and for vacuuming up address books, buddy lists, telephone logs and the geographic data embedded in photographs when someone sends a post to the mobile versions of Facebook, Flickr, LinkedIn, Twitter and other Internet services, it said.
The trawling done by the spy agencies scoops up location, age, sex and other personal information of the users.
The eavesdroppers' pursuit of mobile networks has been outlined in earlier reports, but the secret documents offer more details of their ambitions for smartphones and the apps that run on them.
The efforts were part of an initiative called "the mobile surge," according to a 2011 British document, an analogy to the troop surges in Iraq and Afghanistan. An NSA analyst's enthusiasm was evident in the breathless title "Golden Nugget!" given to a slide for a top-secret talk in 2010 that described iPhones and Android phones as rich resources, the report said.
The scale and the specifics of the data haul are not clear, it said. The agencies have the ability to tap both old and new apps like Angry Birds, the documents show, but they do not make explicit whether the spies have put that into practice.
President Barack Obama announced new restrictions this month to better protect the privacy of ordinary Americans and foreigners from government surveillance, including limits on how the NSA can view the metadata of Americans' phone calls.
However, he did not address the information that the intelligence agencies get from leaky apps and other smartphone functions.