The Edward Snowden documentary Citizenfour has won the Oscar for best documentary at the 87th Academy Awards. Laura Poitras’ film documents her initial meeting in Hong Kong with Snowden, as well as journalist Glenn Greenwald. It is an uncommonly intimate view of what became a historic and much debated act: Snowden leaking National Security Agency documents that revealed the previously undisclosed collection of Americans’ phone and email records. Snowden's cache of documents have since unravelled numerous other revelations of massive espionage, affecting several countries including China. "When Laura Poitras asked me if she could film our encounters, I was extremely reluctant. I'm grateful that I allowed her to persuade me," Snowden said on the win. "The result is a brave and brilliant film," Snowden said, adding that he wished more people would see it so that they could "be inspired by its message that ordinary citizens, working together, can change the world." The South China Morning Post interviewed Snowden during his stay in Hong Kong after he fled the US, releasing a trove of information about NSA snooping on targets in Hong Kong and mainland China. The leaked documents also revealed the Prism programme, which gave the US far-reaching access to internet browsing data from Google, Facebook, Apple, Skype, Yahoo and others. Like Poitras's meetings with Snowden, his Post interview in Hong Kong was conducted under secrecy. Snowden was charged under the federal Espionage Act and is currently living in asylum in Russia. Because of the sensitive nature of the footage, Poitras made Citizenfour under intense secrecy and edited it in Germany. The other nominees for best documentary were: Virunga , Last Days of Vietnam , The Salt of the Earth and Finding Vivian Maier . WATCH: Trailer for the now Oscar-winning 'Citizenfour'