A computer with a series of numbers and the logo of the United States' National Security Agency (NSA) is seen in this multiple exposure picture illustration taken in Frankfurt Oct. 28, 2013.KAI PFAFFENBACH/Reuters
As the global furor over U.S. spying activities grows, the country's top intelligence officials take the hot seat in Washington D.C. (1:30 p.m. ET) before a congressional committee poised to ask sharp questions about spying on leaders of friendly nations and why President Barack Obama was unaware.
The flow of revelations that started in June with leaked classified documents detailing the scope of domestic spying – which included collecting phone records and tapping the Internet services of millions of ordinary Americans – took a major twist last week when it was reported that the U.S. was monitoring the cell phone communications of German Chancellor Angela Merkel for over 10 years.
But U.S. surveillance activities by the National Security Agency (NSA) did not stop at heads of states.
Documents obtained by the former NSA contractor Edward Snowden and leaked to U.S. journalist Glenn Greenwald also detail massive surveillance programs and data mining operations targeting tens of millions of French and Spanish citizens.
But much of the focus has been on U.S. snooping on 35 foreign leaders – many believed to be U.S. allies.
Following news that Ms. Merkel's cell phone had been monitored, the German leader spoke directly with Mr. Obama who apologized and reportedly assured the German leader that had he known about the monitoring he would have ordered it to stop.
Why the U.S. president was not in the loop about the monitoring of leaders of friendly nations is a question U.S. lawmakers will put to General Keith Alexander, the director of the NSA, and James Clapper, director of national intelligence.
Lawmakers will also come down hard on the pair over keeping U.S. Congress, include the committee, informed about the extent of the NSA's activities.
In a U.S. television interview on Monday, Mr. Obama said a review of the NSA's domestic and foreign surveillance programs was underway.
Critics of the far-reaching surveillance programs fear that the NSA has been allowed to operate unchecked – using new and sophisticated technologies to snoop on citizens at home and abroad who often have nothing to do with terrorist activities.
Mr. Obama explained that his administration provided the NSA with "policy direction."
"But what we've seen over the last several years is their capacities continue to develop and expand, and that's why I'm initiating now, a review to make sure that what they're able to do, doesn't necessarily mean what they should be doing," said Mr. Obama.
The congressional committee will also press intelligence officials today over whether eavesdropping on leaders of friendly nations will stop. So far, the Obama administration has not given a firm sign that, in fact, it will halt any future surveillance of allies like German Chancellor Angela Merkel. Senator Dianne Feinstein who is the chair of the U.S. senate intelligence committee released a statement Monday saying she was "totally opposed" to spying on world leaders who were allies.
There has been a strong backlash in Europe and South America over the stream of revelations regarding NSA activities. In September, Brazilian President Dilma Rousseff cancelled a state visit to the U.S. over reports of the NSA spying on her personal communications.
The global spying saga took another twist on Monday when the Spanish daily El Mundo reported that the U.S. National Security Agency (NSA) was behind the monitoring of 60 million phone calls made in Spain in the span of one month. The news followed from last week's revelations that the NSA was involved in similar surveillance activities involving 70 million French citizens.
In the case of Spain, there is no suggestion that the content of calls were monitored. Instead, the NSA collected "metadata" – who was making calls, where the calls were made from, and what time of day the calls were made.
Last week, Le Monde published details of similar surveillance program of French phone calls by the NSA – except the newspaper alleged that documents showed that conversations were recorded, but only when calls were being made from specific phone numbers.
American ambassadors in Paris and Madrid have been summoned to answer the allegations that the U.S. government collected phone data on millions of ordinary French and Spanish citizens.
Meanwhile, delegations of European lawmakers and spymasters are already in Washington D.C. to grill Obama administration officials and U.S. politicians.
The spying controversy marks a low point in relations between the U.S. and Europe.
Ms. Merkel told reporters last week that allies needed to trust each other and that "such trust now has to be built anew."