Edward Snowden, the former NSA contractor who leaked top-secret documents on the agency’s surveillance programs, said that the calls for reforms to the National Security Agency prove his leaking was justified.

Snowden wrote “A Manifesto for the Truth,” published in the German news magazine Der Spiegel on Sunday, in which he said the revelations that stemmed from his leaks have helped bring change to surveillance practices.

“Instead of causing damage, the usefulness of the new public knowledge for society is now clear because reforms to politics, supervision and laws are being suggested," Snowden wrote, according to Reuters.

"Citizens have to fight against the suppression of information about affairs of essential importance for the public. Those who speak the truth are not committing a crime."

Snowden is wanted in the United States on espionage charges and has been granted temporary asylum in Russia, where he currently resides, for at least a year.

The stories resulting from Snowden’s documents on the NSA’s spying have sent shockwaves across the globe, including in Germany, where it was revealed the NSA had spied on German Chancellor Angela Merkel.

Snowden said that governments launched a “persecution campaign” against him because they felt exposed by his revelations and were trying to repress debate.

"At that time the public was not in a position to judge the usefulness of these revelations. People trusted that their governments would make the right decisions," he wrote, according to Reuters.

"Today we know that was a mistake and that such behavior does not serve the public interest," he said.