The federal government collected tens of thousands of emails of Americans as part of a massive surveillance program to combat terrorism that was designed to target foreigners, according to secret documents declassified Wednesday.
The violation was discovered in 2011 only after the National Security Agency had collected as many as 56,000 emails annually by Americans over three years.
Days later, members of Congress on the Intelligence and Judiciary committees and the secret court that oversees NSA surveillance programs, the Foreign Intelligence Surveillance Court, learned of the breach.
The court then ruled the program unconstitutional, forcing the NSA to change its practices and segregate collections most likely to contain Americans' emails.
John Bates, who was then the court's chief judge, said in his ruling that it was the "third instance in less than three years in which the government has disclosed a substantial misrepresentation regarding the scope of a major collection program."
"For the first time, the government has now advised the court that the volume and nature of the information it has been collecting is fundamentally different from what the court had been led to believe," Bates wrote in October 2011.
The documents were declassified late Wednesday by James Clapper, the director of national intelligence, after a directive by President Barack Obama to try to quell growing public consternation over the government's vast – and largely secret – surveillance programs. The documents are available on a new government website, http://icontherecord.tumblr.com/.
Democratic and Republican lawmakers, many whom have been calling for more oversight for such programs for months, reacted with concern Wednesday.
"Mass collection of Americans' emails without a warrant is unacceptable, and I believe it is unconstitutional," said Sen. Tom Udall, D-N.M. "We need to ensure the government is focused on foreign threats and terrorism, not mass collection of communication by innocent American citizens."
Sen. Bob Corker of Tennessee, the top Republican on the Foreign Relations Committee, wrote a letter to Obama on Wednesday asking for a briefing for senators by Sept. 13 on all surveillance programs.
"Given the scope and scale of the disclosures to date, and the significant likelihood of more to come, it is now all the more important that the administration come to Congress and provide a full accounting of the totality of these efforts," Corker said.
Leaks of top-secret documents by former NSA contractor Edward Snowden in June showed that the NSA is collecting the telephone records of tens of millions of Verizon customers as well as emails through nine companies, including tech giants Microsoft, Yahoo, Google and Facebook.
Since then, several news organizations have released more information on the programs. On Wednesday, The Wall Street Journal reported that current and former officials say U.S. intelligence agencies have built a surveillance system with the capacity to reach as much as 75 percent of U.S. Internet traffic and that, in some cases, it retains the content.
White House spokesman Josh Earnest described the surveillance as a "narrowly focused program that aims specifically at foreign intelligence."
"There are very strict compliance standards in place at the NSA that monitor for compliance issues, that tabulate them, that document them and that put in place measures to correct them when they occur," Earnest said.
Obama recommended a series of changes to surveillance programs – including more transparency and oversight – two weeks ago to allay concerns. But he failed to address calls by lawmakers and experts to overhaul Section 702 of the 2008 Foreign Intelligence Surveillance Act Amendments. The law allows the NSA to search vast databases of individual Americans' emails without court warrants.
Sen. Richard Blumenthal, D-Conn., who's called for a special advocate to represent Americans' privacy rights before the secret court, said the NSA mistake was a "highly intrusive breach." He said it "shows once again the need for strong and effective oversight of government surveillance."
"Now the question is how many other such unconstitutional practices occurred without the court knowing," he said, "and without a special advocate to blow the whistle?"
In 2008, the NSA began collecting large swaths of emails that were to, or from, foreigners of interest or mentioned email addresses of foreigners of interest, according to officials who provided information to reporters Wednesday but weren't authorized to speak publicly.
But the NSA was unable to segregate the emails of Americans.
"On occasion," one of the officials said, "some of those might prove to be wholly domestic."
About 250 million Internet communications were collected each year, according to the documents. As many as 56,000 were Americans' emails.
The violation was discovered three years later as part of a routine oversight process that includes the NSA and the Justice Department. Last year, the NSA destroyed those emails.
"They were having a discussion and a light bulb went off on somebody's head and said, 'Oops, this may be a problem,'" an official said.
By Anita Kumar and Lesley Clark
McClatchy Washington Bureau