A U.S. surveillance court has given the National Security Agency no limit on the number of U.S. telephone records it collects in the name of fighting terrorism, the NSA director said Thursday. 
 
 The NSA intends to collect all U.S. telephone records and put them in a searchable “lock box” in the interest of national security, General Keith Alexander, the NSA’s director, told U.S. senators. 
 
 “There is no upper limit” on NSA telephone-records collection, Alexander said. “I believe it is in the nation’s best interest to put all the phone records into a lock box that we can search when the nation needs to do it.” 
 
 The NSA would need to notify the U.S. Foreign Intelligence Surveillance Court and Congress before collecting some other types of U.S. communications, including mobile-phone location information, Alexander told senators. The NSA doesn't currently have plans to collect mobile-phone location information, he said. 
 
 Alexander, other intelligence officials and several members of the Senate Select Committee on Intelligence defended the NSA’s data collection and surveillance efforts during a committee hearing. 
 
 The NSA collection of U.S. phone records, disclosed by former NSA contractor Edward Snowden earlier this year, are “lawful, effective and constitutional,” said Senator Dianne Feinstein, a California Democrat and chairwoman of the committee. 
 
 Nevertheless, Feinstein said she's working on a bill that would add transparency to the data collection process at the NSA and the surveillance court. Some of the provisions she described would reinforce current NSA practices, but the bill would also give the NSA new authority to continue to conduct surveillance on foreign suspects who enter the U.S. while the agency seeks court-ordered warrants. 
 
 Feinstein, chairwoman of the committee that's supposed to oversee the NSA surveillance programs, at one point interrupted witness Tim Edgar, a former director of privacy and civil liberties for the White House, when he talked about the NSA's unauthorized collection of some U.S. communications. Feinstein defended the NSA, saying the agency immediately reported the mistake to the surveillance court. 
 
 "I really believe the NSA is extraordinarily careful in what they do," she said. "I have great faith in the NSA." 
 
 NSA mistrust? 
 
 Alexander, Director of National Intelligence James Clapper, and some committee members blamed what they called inaccurate media reports on the Snowden leaks for creating an environment of mistrust in the NSA by the general public. 
 
 Some media organizations are feeding “raw meat to people who refuse to look at the facts” that the NSA’s data collections are legal and protect privacy, said Senator Dan Coats, an Indiana Republican. 
 
 “It’s very frustrating to know that we have programs that comply with the law, that have been approved by the Congress, that have been approved by the president of the United States, that are saving Americans’ lives, and there are efforts to compromise those programs to convince a nontrusting public,” Coats said. “Had we not had these programs in place, I’d hate to think of what we’d be talking about” at the hearing. 
 
 Clapper agreed with Coats. Intelligence officials are frustrated in their efforts to “counter the popular narrative” about the surveillance programs, he said. 
 
 But Senator Ron Wyden, an Oregon Democrat and critic of the NSA programs, pointed his finger back at U.S. intelligence officials. Abuses alleged in the NSA programs were bound to be made public, said Wyden, who introduced legislation Wednesday that would prohibit bulk collection of phone records by the NSA. 
 
 “I believe that any government official who thought that the intrusive, constitutionally flawed surveillance system would never be disclosed was ignoring history,” Wyden said. “The leadership of your agencies built an intelligence collection system that repeatedly deceived the American people. Time and time again, the American people were told one thing about domestic surveillance in public forums, while government agencies did something else in private.” 
 
 Updated at 3:25 p.m. PT with additional information about mobile-phone location data collection. ||||| Story highlights The agency found at least 12 cases of misuse 
 
 The NSA has been under fire after the leak of information by a former contractor 
 
 A senator had asked the NSA to detail any abuse of its systems 
 
 The National Security Agency's internal watchdog detailed a dozen instances in the past decade in which its employees intentionally misused the agency's surveillance power, in some cases to snoop on their love interests. 
 
 A letter from the NSA's inspector general responding to a request by Sen. Chuck Grassley, R-Iowa, lists the dozen incidents where the NSA's foreign intelligence collection systems were abused. The letter also says there are two additional incidents now under investigation and another allegation pending that may require an investigation. 
 
 At least six of the incidents were referred to the Justice Department for possible prosecution or additional action; none appear to have resulted in charges. The letter doesn't identify the employees. 
 
 Several of the cases involve so-called "Loveint" violations. 
 
 In one case, detailed by the NSA's watchdog, a civilian intelligence employee assigned overseas was found to have used the NSA's signals intelligence collection system to listen to the phone conversations on nine phone numbers belonging to foreign women from 1998 to 2003 without any valid reason. The signals intelligence system is used to spy on foreign targets for national security reasons. 
 
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 10 photos: Sharing secrets: U.S. intelligence leaks 10 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 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 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 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 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 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 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 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 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 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 
 
 Yahoo and Facebook ask for more NSA transparency 
 
 The case began because a woman, a foreign national employed by the U.S. government, told another employee she suspected the man with whom she was in a sexual relationship was listening to her calls. The employee who misused the NSA's systems also incidentally collected the communications of a U.S. resident on two occasions, a move that requires a court warrant. 
 
 The NSA's vast surveillance powers are under fire after the disclosure of internal documents by former NSA contractor Edward Snowden. Intelligence officials have sought to defend the NSA's surveillance activities by saying the agency doesn't misuse its authority. 
 
 Grassley wrote to the NSA last month seeking to find out how often the NSA's authorities are misused. 
 
 "I appreciate the transparency that the Inspector General has provided to the American people," Grassley said in a statement. "We shouldn't tolerate even one instance of misuse of this program. Robust oversight of the program must be completed to ensure that both national security and the Constitution are protected." 
 
 NSA violated phone rules, misinformed secret court 
 
 In many cases the employees who intentionally abused the NSA's spying systems resigned before they could be punished. Several were demoted in rank or otherwise sanctioned. 
 
 In one 2004 case, a civilian employee told NSA security that she had spied on a foreign phone number because she found it on her husband's cell phone and suspected he was being unfaithful. She collected his phone calls. The employee's infraction was referred to the Justice Department, but she resigned before she could be fired. 
 
 Some of the violations appear to have been uncovered by the NSA's own auditing systems.Others were self-reported, including one during a polygraph of an employee. 
 
 One employee violated NSA's rules on the first day he had access to the agency's signals intelligence collection system. 
 
 He queried six e-mail addresses belonging to a former girlfriend. He told investigators he wanted "to practice on the system" using his former girlfriend's e-mail addresses and that he received no information, and hadn't read any emails. He was demoted and his pay was reduced, and the NSA's inspector general recommended he not be given a security clearance. ||||| National Security Agency Director Keith Alexander said the NSA wants to collect more phone records, even after being the subject of recent public unease. 
 
 Sen. Mark Udall (D-Colo.) asked Alexander if the NSA wants "the phone records of all Americans" during a congressional hearing Thursday. 
 
 "I believe it is in the nation's best interest to put all the phone records into a lockbox that we can search when the nation needs to do it, yes," Alexander replied. 
 
 Sen. Mark Warner (D-Va.) reminded Alexander of Americans' distrust in the NSA since Edward Snowden disclosed documents on previously secret U.S. internet and phone surveillance programs in June. 
 
 "A lot of Americans have lost trust in what you're doing," Warner said. 
 
 During the same hearing, James Clapper, Director of National Intelligence, said he would consider limits to ease concerns raised by disclosures of NSA's bulk collection of Americans' phone and email data. 
 
 Matt Sledge contributed to this report.
– We've heard that the NSA kept an eye on Martin Luther King and Muhammad Ali, but it seems there were also lower-profile targets: some of its own employees' lovers. It's referred to as "loveint" (as in, collecting intel on love interests), and the NSA says it's happened 12 times since 2003, with several more possible instances needing further investigation. In one case, a worker kicked off his very first day of being allowed on the agency's signals intelligence collection system by checking out six of an ex's email addresses; he was doing it for "practice," he said to investigators. He got a demotion, his pay docked, and a recommendation against security clearance, CNN reports. Another employee, who has since resigned, investigated a foreign phone number she'd spotted on her husband's phone, fearing he was having an affair. In other NSA news, a surveillance court has told the NSA there's "no upper limit" on how many phone records it can collect, its director says, per PC World. Asked whether the agency wants all Americans' phone records, director Gen. Keith Alexander told senators, per the Huffington Post: "I believe it is in the nation's best interest to put all the phone records into a lockbox that we can search when the nation needs to do it, yes."