Story highlights White House: Audit shows NSA's efforts to find, address privacy violations

NSA admits "mistakes" do occur, insists most are quickly addressed

Washington Post counts 2,776 incidents -- violations of rules of court orders on surveillance

Congressional leaders express concern about mistakes, call for more oversight

The National Security Agency spent Friday on the defensive, after details got out about an internal audit that found the agency had broken privacy rules "thousands of times each year" since 2008.

The audit was first reported by the Washington Post on Thursday, setting off another round of heated discussion -- and criticism -- in Washington over how the NSA had wrongly impinged on Americans' privacy.

"I ... will continue to demand honest and forthright answers from the intelligence community," said Sen. Patrick Leahy, D-Vermont, noting the Senate Judiciary Committee he chairs will hold a hearing on the Post's revelations. "I remain concerned that we are still not getting straightforward answers from the NSA."

In a call with reporters Friday, John DeLong -- the NSA's director of compliance -- acknowledged "mistakes occur," even as he insisted only a "tiny" amount of such problems were intentional.

"No one at NSA thinks a mistake is OK," DeLong said several times in the call, which a spokesman said was conducted to "address inaccuracies."

NSA leaker Edward Snowden -- whose ongoing leaks have riled the Obama administration and intelligence community -- provided the material to the Post earlier this summer.

Photos: Sharing secrets: U.S. intelligence leaks Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – John Walker ran a father and son spy ring, passing classified material to the Soviet Union from 1967 to 1985. Walker was a Navy communication specialist with financial difficulties when he walked into the Soviet Embassy and sold a piece of cyphering equipment. Navy and Defense officials said that Walker enabled the Soviet Union to unscramble military communications and pinpoint the location of U.S. submarines at all times. As part of his plea deal, prosecutors promised leniency for Walker's son Michael Walker, a former Navy seaman. Click through the gallery to see other high-profile leak scandals the United States has seen over the years. Hide Caption 1 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Military analyst Daniel Ellsberg leaked the 7,000-page Pentagon Papers in 1971. The top-secret documents revealed that senior American leaders, including three presidents, knew the Vietnam War was an unwinnable, tragic quagmire. Further, they showed that the government had lied to Congress and the public about the progress of the war. Ellsberg surrendered to authorities and was charged as a spy. During his trial, the court learned that President Richard Nixon's administration had embarked on a campaign to discredit Ellsberg, illegally wiretapping him and breaking into his psychiatrist's office. All charges against him were dropped. Since then he has lived a relatively quiet life as a respected author and lecturer. Hide Caption 2 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Jonathan Pollard is a divisive figure in U.S.-Israeli relations. The former U.S. Navy intelligence analyst was caught spying for Israel in 1985 and was sentenced in 1987 to life imprisonment. Previously, the United States and Israel discussed his possible release as part of efforts to save fragile Middle East peace negotiations, according to sources familiar with the talks. On July 28, 2015, Pollard's lawyer announced that the convicted spy had been granted parole and would be released on November 21 -- exactly 30 years after his arrest. Hide Caption 3 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Wen Ho Lee was a scientist at the Los Alamos Laboratory in New Mexico who was charged with 59 counts of downloading classified information onto computer tapes and passing it to China. Lee eventually agreed to plead guilty to a count of mishandling classified information after prosecutors deemed their case to be too weak. He was released after nine months in solitary confinement. Lee later received a $1.6 million in separate settlements with the government and five news agencies after he sued them, accusing the government of leaking damaging information about him to the media. Hide Caption 4 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Members of the Bush administration were accused retaliating against Valerie Plame, pictured, by blowing her cover in 2003 as a U.S. intelligence operative, after her husband, former Ambassador Joe Wilson, wrote a series of New York Times op-eds questioning the basis of certain facts the administration used to make the argument to go to war in Iraq. Hide Caption 5 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – In 2007, Lewis "Scooter" Libby, Vice President Dick Cheney's former chief of staff, was convicted on charges related to the leak of the identity of CIA operative Valerie Plame. Libby was convicted of obstruction of justice and perjury in connection with the case. His 30-month sentence was commuted by President George W. Bush. Cheney told a special prosecutor in 2004 that he had no idea who leaked the information. Hide Caption 6 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Aldrich Ames, a 31-year CIA employee, pleaded guilty to espionage charges in 1994 and was sentenced to life in prison. Ames was a CIA case worker who specialized in Soviet intelligence services and had been passing classified information to the KGB since 1985. U.S. intelligence officials believe that information passed along by Ames led to the arrest and execution of Russian officials they had recruited to spy for them. Hide Caption 7 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Robert Hanssen pleaded guilty to espionage charges in 2001 in return for the government not seeking the death penalty. Hanssen began spying for the Soviet Union in 1979, three years after going to work for the FBI and prosecutors said he collected $1.4 million for the information he turned over to the Cold War enemy. In 1981, Hanssen's wife caught him with classified documents and convinced him to stop spying, but he started passing secrets to the Soviets again four years later. In 1991, he broke off relations with the KGB, but resumed his espionage career in 1999, this time with the Russian Intelligence Service. He was arrested after making a drop in a Virginia park in 2001. Hide Caption 8 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Army Pvt. Bradley Manning was convicted July 30 of stealing and disseminating 750,000 pages of classified documents and videos to WikiLeaks, and the counts against him included violations of the Espionage Act. He was found guilty of 20 of the 22 charges but acquitted of the most serious charge -- aiding the enemy. Manning was sentenced to 35 years in military prison in 2013. Hide Caption 9 of 10 Photos: Sharing secrets: U.S. intelligence leaks Sharing secrets: U.S. intelligence leaks – Former intelligence contractor Edward Snowden revealed himself as the leaker of details of U.S. government surveillance programs run by the U.S. National Security Agency to track cell phone calls and monitor the e-mail and Internet traffic of virtually all Americans. Snowden has been granted temporary asylum in Russia after initially fleeing to Hong Kong. He has been charged with three felony counts, including violations of the U.S. Espionage Act, over the leaks. Hide Caption 10 of 10

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The May 2012 audit found 2,776 incidents of "unauthorized collection, storage, access to or distribution of legally protected communications" in the preceding 12 months, the Post reported in its story

"Most were unintended. Many involved failures of due diligence or violations of standard operating procedure," said the Post article by reporter Barton Gellman. "The most serious incidents included a violation of a court order and unauthorized use of data about more than 3,000 Americans and green-card holders."

Leahy was not the only lawmaker, nor the only member of President Barack Obama's Democratic party, to call for more oversight and hearings.

"Press reports that the National Security Agency broke privacy rules thousands of times per year and reportedly sought to shield required disclosure of privacy violations are extremely disturbing," said House Minority Leader Nancy Pelosi.

Pelosi called for "rigorous oversight" by Congress on the "incidents of non-compliance."

Another Democrat from California, Senate Intelligence Committee chairwoman Sen. Dianne Feinstein, told the Post in a statement late Thursday night that her committee "can and should do more to independently verify that NSA's operations are appropriate, and its reports of compliance incidents are accurate."

The Washington Post reported that most incidents involved unauthorized surveillance of Americans or foreign intelligence targets in the country. In one case, the NSA decided it didn't need to report the unintended surveillance.

In 2008, a "large number" of calls placed from Washington were intercepted due to a programming error that confused the capitol's 202 area code for 20, the international dialing code for Egypt. The information came from a "quality assurance" review that wasn't distributed to the NSA overnight staff, according to the Post.

Separately, an NSA new collection method went undiscovered by the Foreign Intelligence Surveillance Court for months. The court, which has authority over some of the agency's operations, ruled it unconstitutional.

Responding to the Post's story, the NSA said, "A variety of factors can cause the numbers of incidents to trend up or down from one quarter to the next."

Factors can include implementation of new procedures, technology or software changes and expanded access.

"The one constant across all of the quarters is a persistent, dedicated effort to identify incidents or risks of incidents at the earliest possible moment, implement mitigation measures wherever possible, and drive the numbers down," the agency said.

The agency released another statement Thursday night defending its programs.

"NSA's foreign intelligence collection activities are continually audited and overseen internally and externally," it said. "When NSA makes a mistake in carrying out its foreign intelligence mission, the agency reports the issue internally and to federal overseers -- and aggressively gets to the bottom of it."

On Friday, DeLong said his agency "detects and corrects mistakes" as these occur and are identified, which stops them from being "propagated."

"The NSA has zero tolerance for misconduct," he said, noting that those who make repeated mistakes lose access to key databases.

Overall, DeLong insisted, the NSA carefully adheres to privacy protections.

White House spokesman Josh Earnest offered a similar statement Friday, saying the NSA compliance office's review reflects its commitment to abiding by the law and protecting people's privacy.

"The documents demonstrate that the NSA is monitoring, detecting, addressing and reporting compliance incidents," Earnest said.

The man who leaked the audit to the Post, Snowden, stepped forward publicly in June to claim responsibility for leaking to the media that the NSA had secretly collected and stored millions of phone records from accounts in the United States. The agency also collected information from U.S. companies on the Internet activity of overseas residents, he said.

Snowden fled first to Hong Kong and then to Russia before Moscow granted him temporary asylum despite pressure from the Obama administration to return him to the United States to face charges.

He has been charged with three felony counts, including violations of the U.S. Espionage Act, for the leaks.

Although polling shows Americans harbor skepticism of the domestic surveillance programs Snowden revealed, a majority of Americans don't approve of the actions he took and they think he, as an American citizen, should be brought to justice.

A CNN/ORC International survey released last month indicated that 52% of the public disapproved of Snowden's actions, while 44% said they approved of the leaks. Fifty-four percent of those questioned in the poll said the government should attempt to bring Snowden back to the United States and prosecute him for his leaks.

As for the program Snowden revealed, there is a noticeable generational divide on the surveillance tactics, with younger Americans more likely to support Snowden than older Americans.