Snowden is wanted in the United States on charges of espionage after leaking secret documents to journalists that revealed extensive spying on U.S. citizens and international leaders by the U.S. National Security Agency.
Interviewed in a Moscow hotel, Snowden said he leaked the revelations because he was a "patriot."
He denied he was working with the Russian government, which has given him asylum.
Earlier on May 28, U.S. Secretary of State John Kerry said Snowden had seriously damaged U.S. security by leaking intelligence and had "betrayed his country."
Kerry said Snowden should "man up" and return to the United States for trial.