There’s no end in sight to the leak on US government surveillance programs by Edward Snowden, even as the whistleblower has sought asylum in Russia after promising that he wouldn’t continue to harm US interests.

Despite that promise, The Washington Post yesterday published an internal audit and various other classified documents that show how the National Security Agency (NSA) has repeatedly broken privacy laws and overstepped legal boundaries on thousands of ocassions since it was granted extensive powers back in 2008.

In many of the cases, the NSA was carrying out unauthorized surveillance on American citizens, despite the practice being restricted by law and executive orders. Due to numerous infractions that ranged from typographical errors to significant violations of US law, the NSA reportedly also intercepted thousands of emails and phone calls unintentionally.

Even more worrying is that, according to the Washington Post, the audit obtained by Snowden only covered a period of 12 months up to May 2012, which means that the NSA has likely made thousands more such violations before and since. As for the audit itself, this counted a total of 2,776 incidents in which the NSA collected, stored, accessed or distributed communications that are supposed to be protected by law – the vast majority of which were unintentional. In many of these cases, the incidents occurred due to violations of the NSA’s standard operating procedure, or to failures of due diligence. However, there were also some serious incidents, including one where officials violated a court order and another case where data on more than 3,000 US citizens and green-card holders was used illegally.

The disclosure that the NSA is routinely breaking privacy laws comes at the same time as the leader of the Foreign Intelligence Surveillance Court (FISC) court (which provides oversight for PRISM and other spying programs) revealed that it’s ability to maintain checks on the agency is extremely limited.

According to a separate report in the WP, Judge Reggie B. Walton admitted that it’s almost impossible for the FISC court to independently verify whether or not the NSA’s surveillance breaks privacy laws, and must instead rely on the government to own up to any such violations. Moreover, even when the government does admit to violations, FISC is unable to check official’s assertions that these incidents are unintentional, as they often claim.

“The FISC is forced to rely upon the accuracy of the information that is provided to the Court,” said Judge Walton to the Washington Post.

“The FISC does not have the capacity to investigate issues of noncompliance, and in that respect the FISC is in the same position as any other court when it comes to enforcing [government] compliance with its orders.”

As for the NSA itself, an unnamed senior official speaking with permission from White House chiefs told the paper that such violations were unintentional, but at the same time unavoidable:

“We’re a human-run agency operating in a complex environment with a number of different regulatory regimes, so at times we find ourselves on the wrong side of the line.”