LOS ANGELES: Oscar-winning filmmaker Kathryn Bigelow's long-awaited movie about the hunt for and killing of Osama bin Laden is generating Academy Awards buzz, even before its release next month.

The director, who won Academy Awards in 2010 for Iraq war drama “The Hurt Locker,” had extensive access to classified material in the making of “Zero Dark Thirty,” a process that began long before bin Laden's death in May 2011.

The movie centers on a female CIA analyst - played by Jessica Chastain - credited as a key force in the hunt for the Al Qaeda chief, killed by US Navy SEALs in an audacious dead-of-night raid on his hiding place in Pakistan.

'Zero Dark Thirty' could well be the most impressive film Bigelow has made, as well as possibly her most personal,” commented the Hollywood Reporter, after initial screenings of the movie.

“The film's power steadily and relentlessly builds over its long course, to a point that is terrifically imposing and unshakable,” it added.

Variety said the movie was “far more ambitious than 'The Hurt Locker,' yet nowhere near so tripwire-tense,” hailing it for “rejecting nearly every cliche one might expect from a Hollywood treatment of the subject.” The Los Angeles Times said “Zero Dark Thirty” - military-speak for half past midnight, when the bin Laden raid was scheduled for - entered its Oscar best picture league table at number five.

Entertainment Weekly tipped it as a possible nominee for best film, best director, best screenplay and best leading actress for Chastain, who was Oscar nominated for her supporting role in last year's civil rights drama “The Help.” The two-and-a-half-hour long docudrama follows the CIA analyst over her decade-long quest to track down bin Laden after the September 11, 2001 attacks on New York and Washington.

It includes graphic torture scenes, including depictions of waterboarding and sexual humiliation, used to obtain information from detainees which ultimately help pinpoint bin Laden's compound in Abbottabad, Pakistan.

“I wish that it wasn't a part of history, but it is and was,” Bigelow was cited as saying after a weekend screening in Los Angeles, adding that the torture scenes were the most difficult for her to film.

The film's screenplay was written by reporter-turned-screenwriter Mark Boal, who also worked with Bigelow on “The Hurt Locker,” which starred Jeremy Renner as a soldier defusing bombs in war-scarred Iraq.

“Zero Dark Thirty” opens in limited release in the United States from December 19, qualifying it for next February's Academy Awards show even though its general release is not until January.