In an interview with the New York Times, Edward Snowden said Russian and Chinese officials did not have access to the classified documents he took while working as an NSA contractor. The files were never taken to Russia, Snowden said, because “because it wouldn’t serve the public interest;” instead, Snowden said he gave all copies of the files to the journalists that met him in Hong Kong.

As for China's authorities accessing the files while he was in Hong Kong, Snowden said his experience as an NSA contractor – he said his last job there was targeting China, and he claims to have taught a course on Chinese cyber-counterintelligence – allowed him to protect the documents. “There’s a zero percent chance the Russians or Chinese have received any documents,” he told the Times.

Snowden explained his motivation for the leaks, telling the Times' James Risen that “the secret continuance of these programs represents a far greater danger than their disclosure.” And he said that if the leaks had actually compromised the NSA's spying operations in China or elsewhere, it would be well-publicized by now.

His last target while working as an agency contractor was China, he said, adding that he had had “access to every target, every active operation” mounted by the N.S.A. against the Chinese. “Full lists of them,” he said.

“If that was compromised,” he went on, “N.S.A. would have set the table on fire from slamming it so many times in denouncing the damage it had caused. Yet N.S.A. has not offered a single example of damage from the leaks. They haven’t said boo about it except ‘we think,’ ‘maybe,’ ‘have to assume’ from anonymous and former officials. Not ‘China is going dark.’ Not ‘the Chinese military has shut us out.’ ”

And Snowden disputed last week's report that he received a derogatory comment from his CIA supervisor in Geneva for attempting to break into classified files; Snowden said he received the comment because he upset his supervisor by pointing out a vulnerability in the software for the C.I.A.’s personnel Web applications.

Mr. Snowden added that inside the spy agency “there’s a lot of dissent — palpable with some, even.” But he said that people were kept in line through “fear and a false image of patriotism,” which he described as “obedience to authority.”

He said he believed that if he tried to question the N.S.A.’s surveillance operations as an insider, his efforts “would have been buried forever,” and he would “have been discredited and ruined.” He said that “the system does not work,” adding that “you have to report wrongdoing to those most responsible for it.”