The May 2012 audit, intended for the agency's top leaders, counts only incidents at NSA's Fort Meade, Md. headquarters and other facilities in the Washington area. Three government officials, speaking on the condition of anonymity to discuss classified matters, said the number would be substantially higher if it included other NSA operating units and regional collection centers.
Senate Intelligence Committee Chairman Dianne Feinstein, D-Calif., who did not receive a copy of the 2012 audit until The Post asked her staff about it, said in a statement late Thursday that the committee "can and should do more to independently verify that NSA's operations are appropriate, and its reports of compliance incidents are accurate."
Despite the quadrupling of NSA's oversight staff after a series of significant violations in 2009, the rate of infractions increased throughout 2011 and early 2012. An NSA spokesman declined to disclose whether the trend has continued since last year.
One major problem is largely unpreventable, the audit says, because current operations rely on technology that cannot quickly determine whether a foreign mobile phone has entered the United States.
In what appears to be one of the most serious violations, the NSA diverted large volumes of international data passing through fiber-optic cables in the United States into a repository where the material could be stored temporarily for processing and selection.
The operation to obtain what the agency called "multiple communications transactions" collected and commingled U.S. and foreign e-mails, according to an article in SSO News, a top-secret internal newsletter of the NSA's Special Source Operations unit. NSA lawyers told the court that the agency could not practicably filter out the communications of Americans.
In October 2011, months after the program got underway, the Foreign Intelligence Surveillance Court ruled that the collection effort was unconstitutional. The court said that the methods used were "deficient on statutory and constitutional grounds," according to a top-secret summary of the opinion, and it ordered the NSA to comply with standard privacy protections or stop the program.