A report published in the Washington Post released some top secret documents about how the National Security Agency (NSA) illegally collects surveillance on Americans, thousands of times per year.
Most of the May 2012 audit is a catalogue of cock-ups where the NSA collected data by accident due to analyst and programming errors.
But in one case the phone records of more than 3,000 US citizens were stored despite the fact that the NSA had been ordered to shred them by a surveillance court.
All up, the audit reported 2,776 cases where the NSA broke its own privacy rules.
In one situation, the spooks mistook the US area code (202) for Washington, DC and the international dialling code for Egypt. As a result, they snooped on a "large number" of domestic American phone calls.
In another case, the NSA mixed US and foreign emails that it collected from tapping into a fibre-optic cable that passes through the United States. It wanted to keep the emails and told the Foreign Intelligence Surveillance Court (FISC) that it couldn't filter out which emails belonged to Americans.
The court said that the email collection effort must stop and it was "deficient on statutory and constitutional grounds".
The audit appears to have been provided to the paper a few months ago by former NSA contractor Edward Snowden. The report was only supposed to be seen by the NSA's top brass and no politicians ever saw it.
More information is expected to be released soon. Glenn Greenwald, the Guardian reporter who has published the most information based on Snowden's leaks, is still working on a pile of them and tweeted that he will be releasing them soon.