WASHINGTON: A 29-year-old government contractor was unveiled Sunday as the source of bombshell leaks about US monitoring of Internet users and phone records.

Edward Snowden told the Guardian newspaper he was motivated solely by a desire to inform the public about the "massive surveillance machine."

"I have no intention of hiding who I am because I know I have done nothing wrong," he said. But with the US government seeking a criminal probe into the leaks, he admitted: "I do not expect to see home again."

The newspaper, which posted a video interview of Snowden clearly showing his face, said it was revealing his identity at his request.

A former technical assistant for the CIA, Snowden worked for four years at the National Security Agency as an employee of various outside contractors, including Dell and Booz Allen Hamilton, his current employer.

"My sole motive is to inform the public as to that which is done in their name and that which is done against them," Snowden said.

Three weeks ago, he packed his bags for Hong Kong and left a salary of about $200,000, a girlfriend with whom he lived in Hawaii, a stable career and a loving family, according to The Guardian.

"I'm willing to sacrifice all of that because I can't in good conscience allow the US government to destroy privacy, Internet freedom and basic liberties for people around the world with this massive surveillance machine they're secretly building," Snowden said.

Director of National Intelligence James Clapper earlier called for a criminal probe into the leaks, slamming the "gut-wrenching" disclosures for causing "huge, grave damage" to US intelligence capabilities.

"The NSA has filed a crimes report on this already," Clapper told NBC, referring to the leaks to The Guardian and The Washington Post.