An Oct. 28, 1985 photo of John A. Walker Jr., being escorted by a federal marshal as he leaves the Montgomery County Detention Center in Rockville, Md., enroute to a federal court in Baltimore. He was ultimately sentenced to life in prison on espionage charges. Bob Daugherty/AP hide caption

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German Foreign Minister Frank-Walter Steinmeier at a news conference at the Foreign Ministry in Berlin on Friday. Steinmeier will meet Secretary of State John Kerry this weekend to discuss allegations of U.S. spying. Michael Sohn/AP hide caption

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Press materials are displayed on a table at the Justice Department in Washington on Monday before Attorney General Eric Holder was to speak at a news conference. Charles Dharapak/AP hide caption

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Russian President Vladimir Putin as he answered questions on national TV Thursday in Moscow. Alexey Nikolsky/RIO Novosti/Kremlin pool/EPA/Landov hide caption

itoggle caption Alexey Nikolsky/RIO Novosti/Kremlin pool/EPA/Landov

Suspected Banksy artwork appears on the side of a house, depicting government agents spying on a phone box near GCHQ (Government Communications Headquarters) in Gloucestershire, England, Sunday. Jules Annan/Barcroft Media/Landov hide caption

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Who else might be watching? Britain's spies collected millions of images from video chats, according to the latest secrets spilled by NSA leaker Edward Snowden. Paul Sakuma/AP hide caption

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Former chief counterterrorism adviser Richard Clarke is a lead member of a panel appointed by the president to review the country's surveillance policies. Alex Wong/Getty Images hide caption

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The seal of the CIA at the agency's headquarters in Virginia. Greg E. Mathieson Sr. /MAI/Landov hide caption

itoggle caption Greg E. Mathieson Sr. /MAI/Landov

German Chancellor Angela Merkel and President Obama in September at the G20 summit in Russia. She and other leaders have objected after hearing that the NSA was listening to their phone calls. Anton Denisov/Host photo agency/Getty Images hide caption

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German Chancellor Angela Merkel (right) talks with Italian Prime Minister Enrico Letta on the second day of an European Council meeting in Brussels on Friday. John Thys/AFP/Getty Images hide caption

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