HONG KONG -- The journalist who exposed classified U.S. surveillance programs leaked by an American defense contractor said Tuesday there will be more 'significant revelations' to come from the documents.
"We are going to have a lot more significant revelations that have not yet been heard over the next several weeks and months," said Glenn Greenwald of The Guardian.
Greenwald told The Associated Press the decision was being made on when to release the next story based on the information provided by Edward Snowden, a 29-year-old employee of government contractor Booz Allen Hamilton who has been accused by U.S. Senate intelligence chairwoman Sen. Dianne Feinstein of California of committing an "act of treason" that should be prosecuted.
Greenwald's reports last week exposed widespread U.S. government programs to collect telephone and Internet records.
"There are dozens of stories generated by the documents he provided, and we intend to pursue every last one of them," Greenwald said.
Snowden's whereabouts were not immediately known on Tuesday, although he was believed to be staying somewhere in Hong Kong.
No charges have been brought and no warrant has been issued for Snowden's arrest.
Snowden sought to leak the story on Washington's eavesdropping through Greenwald, a columnist for a UK-based publication who has made no secret of his distaste for intrusions on privacy.
Snowden brought his information to Greenwald instead of The Washington Post, the more mainstream media outlet with which he had briefly corresponded.
The case illustrates the passion an opinion-driven journalist can bring to a breaking news story, but at the same time it raises questions about fairness.
Greenwald, author of three books in which he argues the government has trampled on personal rights in the name of protecting national security, wrote the original stories exposing the extent of the government's data collection. Over the weekend, he identified intelligence contractor Snowden as his source at Snowden's request.
"What we disclosed was of great public interest, of great importance in a democracy, that the U.S. government is building this massive spying apparatus aimed at its own population," Greenwald said Monday on MSNBC's "Morning Joe."
Greenwald also told The Associated Press he's been contacted by "countless people" over the last 24 hours offering to create legal defense funds for Snowden.
The topic is personal for Greenwald, 46. The former constitutional and civil rights lawyer, educated at the New York University Law School, began the "Unclaimed Territory" blog in 2005 and wrote "How Would a Patriot Act?" a year later. The book criticized the Bush administration for its use of executive power.
Greenwald, now based in Brazil, wrote a regular column for Salon for five years until joining The Guardian last year. He said he wanted to reach a more international audience, a desire that coincided with the news organization's effort to expand its reach in the U.S. market.
One program he wrote about collects hundreds of millions of U.S. phone records. The second program takes in audio, email and other electronic activities primarily by foreign nationals who use providers like Microsoft and Apple. Greenwald described the collection of phone records on Monday as "rampant abuse and it needs sunlight. That's why this person came forward and that's why we published our stories."
On "Morning Joe," he snapped that co-host Mika Brzezinski was using "Obama talking points" when she challenged him with a question.
"The wall of secrecy behind which they operate is impenetrable and it is a real menace to democracy," said Greenwald, who won a 2010 Online Journalism Association award for his coverage of Bradley Manning, who is charged with giving classified documents to WikiLeaks.
Snowden, however, had not just gone to Greenwald with his information. Barton Gellman, of The Washington Post, wrote on Sunday that Snowden had contacted him about the story. He said Snowden had asked that the Post publish within 72 hours the full contents of a presentation he had made about the collection of electronic activity from the Silicon Valley companies.
Gellman said the Post would not make any guarantees and sought the government's views about whether the information would harm national security. The Post eventually agreed to publish a small sample of what Snowden was offering, but Snowden backed away, writing that, "I regret that we weren't able to keep this project unilateral," Gellman wrote.
He then contacted Greenwald, the Post said.
Greenwald's clear point of view doesn't necessarily weaken the story, said Jay Rosen, journalism professor at New York University and author of the Press Think blog.
"In many ways, it strengthens it," he said. Greenwald has a clear stance on privacy and national security, but they aren't partisan; he's criticized Democratic President Barack Obama and his Republican predecessor, George W. Bush. Journalists who have strong viewpoints is a tradition with a long history in the U.S., Rosen said.
"The fact that sources now may choose (outlets) on the basis of commitment is a fact and journalists whose professional stance is no commitment may find themselves at a disadvantage," he said.
Greenwald's known feelings on the issue "does leave a little opening for critics," said Ellen Shearer, head of the national security journalism initiative at Northwestern University. There's always a risk that such passion can work against a journalist; some people would worry that facts contradictory to a predisposed belief could be overlooked.
To this point, Shearer said there's been little pushback on the facts, with the debate primarily about whether the information should be published.
Intelligence officials are investigating the leak and its impact on its programs. Director of National Intelligence James Clapper called the revelation of the intelligence-gathering programs reckless and said it has done "huge, grave damage."
The Guardian took care not to publish material that may help other countries improve their eavesdropping or could put the lives of covert agents at risk, Greenwald said.
"We've published these things they marked 'top secret' that don't actually harm national security but conceal what they've done from the public," he said.
The story is a coup for the Guardian, a U.K.-based independent news organization that started covering the United States more aggressively when it determined that one-third of its web traffic came from the U.S. Offices in New York and Washington were opened in 2011, and the Guardian now has 57 employees in the U.S.
The Guardian doesn't offer its newspaper for sale in the U.S. But web traffic to its news website in the U.S. market has increased 47 percent over last year, and is likely to jump further with this month's exposure.