LOS ANGELES, Feb. 22 (Xinhua) -- "Citizenfour," a documentary concerning U.S. whistleblower Edward Snowden and the National Security Agency (NSA) spying scandal, won the Oscar award for best documentary feature on Sunday night.

Laura Poitras, the director, and Mathilde Bonnefoy and Dirk Wilutzky, the producers, are first-time Oscar winners.

The film chronicles Snowden's effort to securely contact Poitras and Glenn Greenwald in 2013 and meet them in Hong Kong, where Poitras filmed Snowden discussing the thousands of classified NSA documents he was leaking to them, and his motives for doing so.

Poitras flew to Hong Kong in late May 2013, where over the course of eight days she filmed Snowden in his hotel room at the Mira Hotel in Hong Kong. Later, she traveled to Moscow, where she filmed a second interview with Snowden.

"The disclosures of Edward Snowden don't only expose a threat to our privacy but to our democracy itself," said Poitras when receiving the golden statuette at the 87th annual Academy Awards ceremony held at the Dolby Theatre in Hollywood.

"When the decisions that rule us are taken in secret we lose the power to control and govern ourselves," added the director.

Poitras thanked Edward Snowden for his "sacrifices," adding that "I share this award with Glenn Greenwald and the many other journalists who are taking risks to expose the truth."

The film also won the Independent Spirit Award for the best documentary of this year.

Other competitors for this year's Oscar award for best documentary included "Finding Vivian Maier," "Last Day in Vietnam," "The Salt of the Earth" and "Virunga."