Russian government granted him asylum and extended the residency permit in 2017 until 2020.
Read MoreIn 2016, US Congress released a report saying Snowden has been in contact with Russian intelligence officials since his arrival to Russia, a claim Snowden denied. In an interview in September last year, Snowden said he would be willing to return to the US if he is guaranteed a fair trial. "One of the big topics in Europe right now is should Germany and France invite me in to get asylum," he said. "And of course I would like to return to the United States. That is the ultimate goal. But if I'm going to spend the rest of my life in prison, the one bottom-line demand that we all have to agree to is that at least I get a fair trial. And that's the one thing the government has refused to guarantee because they won't provide access to what's called a public interest defense," Snowden told CBS co-hosts Gayle King and Tony Dokoupil on "CBS This Morning."
He added: "I'm not asking for a parade. I'm not asking for a pardon. I'm not asking for a pass. What I'm asking for is a fair trial. And this is the bottom-line that any American should require."