National Security Agency leaker Edward Snowden delivers remarks via video link from Moscow to attendees at a conference on privacy and surveillance issues, in New York City, Sept. 24, 2015. Andrew Kelly/Reuters

Edward Snowden will sue Norway in an attempt to secure free travel to the country, a Norwegian law firm representing him told Reuters Thursday.

The ex-contractor at the U.S. National Security Agency (NSA) has been invited to Norway to receive an award for his work defending free speech, but his attorneys said he is worried that traveling there would allow the Norwegian government to extradite him to the U.S., where he is wanted on charges of espionage. The Norwegian branch of the global organization of writers PEN International, which hopes to give Snowden the free speech award, said in a statement that “we will do our utmost to ensure that Snowden may receive the prize in person.”

The goal of the lawsuit is to establish that Norway has no right to extradite Snowden, his lawyers said in a statement.

“U.S. authorities have already asked that Snowden will be extradited to the U.S. if he was to arrive in Norway,” Hallvard Helle, an attorney representing Snowden, told Reuters. When asked whether Norway had said it would extradite Snowden, Helle replied that the country had not commented, “so therefore we want a legal clarification of this.”

Snowden rose to prominence in 2013 when he leaked secret information about the NSA’s surveillance activities, which made headlines around the world and caused many to question the U.S. government’s intelligence practices. He fled the U.S. in May of that year, going first to China and then to Russia.

He was granted asylum in Russia and has been living there since then, while making occasional appearances at conferences and other events in the U.S. via video links. Some have viewed Snowden as a whistleblower who stood up to the U.S. government and exposed corruption, while others have called him a traitor.

Snowden has an active social media presence now, frequently tweeting about developments in the global intelligence community, as well as politics and other world issues. Just this week, he commented on the news that the U.S. was replacing an image of President Andrew Jackson on the front of the $20 bill with a picture of Harriet Tubman, as he appeared to indicate the abolitionist reminded him of somebody near and dear to his own heart: