FAQ: What we know so far about NSA surveillance

Recent news reports alleging broad surveillance efforts by the U.S. National Security Agency seem to have left more questions than answers. Whistleblower Edward Snowden has accused the NSA of collecting massive amounts of data from U.S. residents, but U.S. officials have largely denied his allegations.

Here's what we know so far, from reports in the U.K.'s Guardian, the Washington Post and other media sources, as well as our own reporting:

1. Snowden has accused the NSA of mass collection of data owned by U.S. citizens. The NSA and U.S. intelligence community is "focused on getting intelligence wherever it can, by any means possible," he told the Guardian. The NSA "targets the communications of everyone. It ingests them by default ... because that's the easiest, most efficient and most valuable way to achieve these ends."