It has resulted in a bipartisan effort in the Senate to declassify secret court orders that authorize the operations, and requests from Google and Facebook for permission to disclose more about National Security Agency requests for users' emails and other online communications.
Calls for greater transparency, rather than new limits on government powers, have been the main public demand since the revealation that the NSA was collecting and analyzing data flowing through nine US internet companies under PRISM programme.
Mozilla, the nonprofit organization behind the popular Firefox Web browser, and 85 other organizations and companies launched a campaign encouraging online users to email Congress with a pre-written letter demanding the government unveil "the full extent of the NSA's spying programs."
"As users, we don't have good ways of knowing whether the current system is being abused because it's all happening behind closed doors," Mozilla explained.
Meanwhile, authorities in Hong Kong declined to comment on Edward Snowden's case. But local officials are unlikely to get involved publicly in the case unless the United States issues a warrant for his arrest.
In US, Justice Department officials said they were moving to finalize charges against Snowden. Given the disclosures, and his own admissions, he is likely to face numerous counts of mishandling and disclosing classified information, and perhaps more serious charges.
The Obama administration fears the 29-year-old computer technician may already have given reporters additional intelligence secrets as part of his self-described campaign to prevent overly intrusive government spying. Snowden had also said he sought to spark a national debate about privacy and national security.
In Washington, NSA Director Keith Alexander briefed a closed meeting of the Senate Intelligence Committee, and the full House was invited to attend a closed-door briefing with senior officials from the NSA, FBI, Justice Department and other agencies.
Review and restrictions
Some lawmakers said they expect a push to review who and how many individuals are granted high-level security clearances. Snowden, a high school dropout who entered the intelligence services as a security guard, was able to access a vast trove of national security secrets.
A bipartisan group of eight senators introduced legislation to declassify significant opinions from the Foreign Intelligence Surveillance Court. The 11-member court meets in secret session to review applications for secret wiretaps, data mining and other surveillance systems used by intelligence agencies.
Transparent demand by Google and Facebook
Amid the raging controversy over Internet surveillance programme, top tech companies in a concerted move have asked the government ease the secrecy surrounding national security investigations.
Google, Facebook and Microsoft in requests echoed by a top official from Twitter also asked US officials to lift long-standing gag orders covering the nature and extent of information collected about internet users by the National Security Agency.
In an open letter to Attorney General Eric H. Holder Jr. and FBI Director Robert S. Mueller III Google sought to be allowed to significantly expand its semiannual "transparency reports" on the information sought by courts and police worldwide.
"Google has nothing to hide," wrote Chief Legal Officer David Drummond.
Facebook soon after issued a statement suggesting that it may start publishing its own "transparency reports" - a move the company has long resisted.
"We urge the United States government to help make that possible by allowing companies to include information about the size and scope of national security requests we receive, and look forward to publishing a report that includes that information," wrote Ted Ullyot, general counsel to Facebook.
Microsoft issued a statement as well, saying that greater transparency "would help the community understand and debate these important issues."
With agencies inputs