The US Department of Homeland Security is warning its employees that they can be punished for opening up this Washington Post article, which includes a classified slide (above) illustrating how the National Security Agency spies on communications:
An internal memo from DHS headquarters told workers on Friday that viewing the document from an "unclassified government workstation" could lead to administrative or legal action. "You may be violating your non-disclosure agreement in which you sign that you will protect classified national security information," the communication said.
The memo said workers who view the article through an unclassified workstation should report the incident as a "classified data spillage."
"DHS warns employees not to read leaked NSA information." [Washington Post]