Edward Snowden, who acknowledged leaking top-secret documents about extensive U.S. surveillance of telephone calls and Internet communications, claimed in an unusual live Web chat Monday that he sees no possibility of a fair trial in the United States and suggested that he would try to elude authorities as long as possible.

The U.S. government has “openly declar(ed) me guilty of treason and (said) that the disclosure of secret, criminal and even unconstitutional acts is an unforgivable crime,” he said. “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.”

Snowden’s remarks came in a question-and-answer session on the website of Britain’s Guardian newspaper. The Guardian and The Washington Post recently published articles about National Security Agency surveillance programs based on documents provided by Snowden. He is believed to have taken the classified material while working as an NSA contractor in Honolulu for the consulting firm Booz Allen Hamilton.

The spectacle of Snowden using the Internet to defend himself and level new accusations was the latest chapter in the unfolding story. The Guardian did not say where Snowden was when he responded to written questions from its reporters and the public. In a note on the site, the newspaper said the discussion was subject to “Snowden’s security concerns and also his access to a secure Internet connection.”

Snowden, 29, emerged June 9 from his status as an anonymous source for the articles. At the time, he was staying in an upscale hotel in Hong Kong, which he said he had chosen because he felt he might win asylum. He gave an interview to a Hong Kong newspaper last week, but since then he has disappeared.

Snowden said in the chat that the U.S. government has accused him of treason, but he faces no known charges. Justice Department officials said a criminal investigation is underway to determine the extent of the damage created by Snowden’s leaks and the nature of any charges he might face.

A former Justice Department official, who spoke on the condition of anonymity because he was not authorized to discuss the case publicly, said officials are probably gathering forensic material that would back up possible criminal charges. They could then file criminal charges in federal court in the District of Columbia or Hawaii or indict Snowden under seal. The official said prosecutors might choose to seal the indictment so Snowden would not know that he was subject to detention and arrest.