US Secretary of State John Kerry invited Snowden to "man up and come back to the United States."
"The bottom line is this is a man who has betrayed his country, who is sitting in Russia, an authoritarian country where he has taken refuge," Kerry told the CBS network.
"If he has a complaint about what's the matter with American surveillance, come back here and stand in our system of justice and make his case," Kerry said.
More top news
The Duke of Cambridge said his children were beginning a "lifetime of friendship" with Canada as they began their tour of the country.
When and where are they on, and how do they work?
What better, more dramatic spectacle has there ever been on American television?