However, it seems that Mr Snowden could buy time, perhaps months, if he opted to stay in Hong Kong - legal technicalities reportedly have rendered the island's asylum laws inoperable and experts say that all current applicants for asylum are entitled to remain in Hong Kong until the legal anomaly is rectified.
Mr Snowden was an employee of the defence and intelligence contractor Booz Allen Hamilton, not directly of the NSA. On Tuesday, the contracting firm issued a brief statement, confirming that Snowden had commenced working for it as recently as March and, in the wake of the leaks, he had been fired.
"Booz Allen can confirm that Edward Snowden, 29, was an employee of our firm for less that three months, assigned to a team in Hawaii," it said. "Snowden, who had a salary of $US122,000, was terminated on June 10, 2013 for violations of the firm's code of ethics and firm policy."
Mr Snowden's 28-year-old girlfriend Lindsay Mills, a ballerina who performs with a Hawaii dance troupe, blogs under the banner 'Adventures of a world-travelling pole-dancing superhero.'
The site was removed soon after Mr Snowden outed himself as the leaker. But in cached versions, Ms Mills writes: "I don't know what will happen from here. I don't know how to feel normal...my world has opened and closed all at once, leaving me lost at sea without a compass - at the moment all I can feel is alone."
Mr Snowden's leaks have left Americans reeling in wonder at the illusory nature of privacy in a post-9/11 world. But some are asking where have they been, suggesting that it is the news media's treatment of the contents of the Snowden leaks that is illusory.
In The Washington Post, the respected columnist Walter Pincus quotes a 2006 report in USA Today, which disclosed that the NSA "has been secretly collecting the phone call records of tens of millions of Americans, using data provided by AT&T, Verizon and BellSouth.
"The NSA program reaches into homes and businesses across the nation by amassing information about the calls of ordinary Americans - most of whom aren't suspected of any crime. This program does not involve the NSA listening to or recording conversations. But the spy agency is using the data to analyse calling patterns in an effort to detect terrorist activity..."
Similarly, Mr Pincus pulled out a March 2012 report from Wired magazine, in which author and intelligence expert James Bamford describes the NSA $US2 billion new data centre in Utah and its capacity to 'intercept, decipher, analyse and store vast swathes of the world's communications as they zap down from satellites and zip through the underground and undersea cables in international, foreign and domestic networks."
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