The NSA insists that it respects American privacy, but documents leaked by Edward Snowden to the Washington Post suggest that the agency has trouble maintaining that respect. A May 2012 audit, buried in the documents, 2,776 incidents where the NSA's Washington-area facilities inadvertently obtained protected American data through a mix of human errors and technical limits. Among its larger gaffes, the NSA regularly had problems determining when foreign cellphones were roaming in the US, leading to unintentional snooping on domestic calls. The agency also spent months tapping and temporarily storing a mix of international and domestic data from US fiber lines until the Foreign Intelligence Surveilliance Court ruled that the technique was unconstitutional. NSA officials responding to the leak say that their agency corrects and mitigates incidents where possible, and argue that it's difficult for the organization to avoid errors altogether. However, the audit also reveals that the NSA doesn't always report violations to overseers -- the division may be interested in fixing mistakes, but it's not eager to mention them.