The best documentary Oscar awarded to "Citizenfour" is the latest in a string of accolades for the journalists who brought to light the trove of classified documents leaked by NSA whistleblower Edward Snowden.
The film directed and produced by Laura Poitras reveals how she worked with other reporters to lift the lid on the sweeping surveillance programs of the US National Security Agency and other intelligence services -- revelations which shocked many in America and around the world.
"The most important decisions being made affecting all of us are made in secret. We lose our ability to check the powers that control," Poitras said Sunday as she accepted the award at the Dolby Theatre in Hollywood, with journalist Glenn Greenwald at her side.
"Thank you to Edward Snowden for his courage and for the many other whistleblowers, and I share this with other journalists who are exposing truth."
Snowden said in a statement released to the American Civil Liberties Union that he hoped people seeing the film would "be inspired by its message that ordinary citizens, working together, can change the world."
"Citizenfour" revolves around a series of conversations with Snowden filmed in Hong Kong, where the onetime NSA contractor explains the powerful intelligence apparatus of the US government and its allies.
It notably shows Snowden -- who used the pseudonym "Citizenfour" when he first contacted Poitras -- explaining these programs to her, Greenwald and Guardian journalist Ewen MacAskill.
Poitras told a recent New York Times forum that the film "has something hopeful in it...  because it's people basically being willing to be courageous and say something about what they see as wrong in the world."
Poitras told AFP in an interview earlier this month in Los Angeles that "the motivation for the film was really to tell the story of what happened, what was the motivation and why (Snowden) took the risks that he took."
The deeply troubling nature of the revelations made these journalists overnight celebrities.
The Guardian and The Washington Post won the Pulitzer Prize last year for reporting on the revelations.
Poitras, who was the point of contact for Snowden, had the unusual distinction of sharing bylines in both the Guardian and the Post on the topic.
The film -- which had a run in theaters before its premiere Monday on premium cable network HBO -- has won a BAFTA, as well as awards from the Directors Guild of America, the National Society of Film Critics and others.
Greenwald, who left the Guardian to join the online news website The Intercept, shared the George Polk Award for National Security reporting, among other prizes.
- Snowden: 'Not about me' -
Snowden, who has been living in exile in Russia as the US government seeks to bring him to trial on espionage charges, told the Times forum that the film is about much more than him.
"Ultimately it's not a film about me, it's a film about us, it's about this journey, about this moment, about this journey of revelation," he said.
"I don't really have a role in it. I've never really been important in it except as an initial mechanism."
He added that he rejected the idea "for a very long time" because "when you are involved in an action that is likely to get you indicted, you typically don't have a camera rolling."
When he did decide to work with Poitras, Snowden said he wanted to make clear it was not "a hostile action" against the government, but action "in the public interest."
Greenwald told the same forum that the film and other reporting based on the Snowden documents have had "an extraordinary impact" worldwide "because the intensity of the debate that has been triggered not just in the United States but globally has changed the consciousness of so many things."