Edward Snowden says he left all classified documents in Hong Kong and took none to Russia after fleeing from his job at the National Security Agency, The New York Times reported Thursday.
The former NSA contractor also said he protected the files from China's intelligence agents.
"There's a zero percent chance the Russians or Chinese have received any documents," he declared in what the newspaper described as an "extensive interview" over several days the past week using encrypted communications.
Snowden, who fled Hawaii in June, defended his actions, maintaining that they helped U.S. national security by igniting a debate about the extent of telephone and Internet surveillance programs. He said their "secret continuance" posed "a far greater danger than their disclosure."
He told the Times he left all sensitive files outlining the agency's surveillance techniques with journalists in Hong Kong before flying on to Moscow, where he has been granted temporarily asylum.
He said it would not "serve the public interest" to have taken the documents to Russia.
"What would be the unique value of personally carrying another copy of the materials onward?" he asked.
The Times writes that Snowden said he made the revelations that he no longer had any NSA documents "to explain why he was confident that Russia had not gained access to them. He had been reluctant to disclose that information previously, he said, for fear of exposing the journalists to greater scrutiny."
U.S. officials have expressed fears that other governments may have obtained the secrets, but Snowden said he believes that the NSA knows he didn't give anything to Russia or China.
Snowden considers himself a whistleblower. The Obama administration has charged him with violating the Espionage Act.
In the interview, the 30-year-old Snowden "offered detailed responses to accusations that have been leveled against him by American officials and other critics, provided new insights into why he became disillusioned with the N.S.A. and decided to disclose the documents, and talked about the international debate over surveillance that resulted from the revelations," the Times writes.