Whistle-blower Edward Snowden last night accused the US government of destroying "any possibility of a fair trial" as he took questions in a live webchat organised by The Guardian newspaper.
It was only the second time Snowden had spoken since revealing himself as the man behind a series of leaks on US cybersurveillance and hacking operations.
He accused the US government of "openly declaring me guilty of treason" and saying that "the disclosure of secret, criminal, and even unconstitutional acts is an unforgivable crime".
"That's not justice, and it would be foolish to volunteer yourself to it if you can do more good outside of prison than in it," he said in reply to a question from Guardian reporter Glenn Greenwald.
He claimed not to have revealed US operations against legitimate military targets, only attacks on civilian infrastructure including hospitals and universities, which he described as "nakedly, aggressively criminal acts".
Asked why he chose to fly to Hong Kong rather than directly to Iceland, the country he claims he wants to seek asylum in, Snowden said: "There was a distinct possibility I would be interdicted en route, so I had to travel with no advance booking to a country with the cultural and legal framework to allow me to work without being immediately detained.
"Hong Kong provided that. Iceland could be pushed harder, quicker, before the public could have a chance to make their feelings known."
Hundreds of questions were posted by readers of the online chat, which started at 11pm Hong Kong time.
"The US Government is not going to be able to cover this up by jailing or murdering me," Snowden said in reply to a question about whether he had made more copies of the documents he disclosed.
Snowden's comments came on the day Beijing responded for the first time to the US cybersnooping programme he exposed, denying an allegation Snowden was spying for Beijing and demanding that Washington explain the operation to the international community.
"It is sheer nonsense," said Foreign Ministry spokeswoman Hua Chunying when asked at a daily news briefing to comment on the allegation put forward by former US vice-president Dick Cheney and other US politicians.
"The US should pay attention to the concerns and demands of the international community and the public over the issue, and provide a necessary explanation to the international community."
On Fox News Sunday, Cheney said China would "probably be willing to provide immunity for [Snowden] or sanctuary for him in exchange for what he presumably knows or doesn't know".