Earlier this year, U.S. Representative Peter King, the Republican who chairs the House committee on Homeland Security, said the filmmakers had "set out to tell a blockbuster, election year story about one of the most classified operations in American history."

King expressed concern about the involvement of a "Democratic lobbying firm" in "brokering" access for the filmmakers to top officials.

But screenwriter Mark Boal said the film is a non-political account of the actions of the undercover operatives who hunted down bin Laden and eventually killed him. Obama is not even a character in the movie, he said.

Sony Pictures said the trailer for the film, titled "Zero Dark Thirty," was released on Tuesday. The studio posted the trailer, which runs for 1 minute 15 seconds, on YouTube.

The trailer is potentially controversial because official documents released by the government this year to a conservative group showed that Boal and film director Kathryn Bigelow were given background briefings by White House, Pentagon and CIA officials about the bin Laden operation.

Both the CIA and the Pentagon said at the time that their interactions with the filmmakers, who won an Oscar for the movie The Hurt Locker, were routine and normal.

A political controversy erupted when New York Times columnist Maureen Dowd reported last year that the White House was "counting on" the film to "counter Obama's growing reputation as ineffectual."

Dowd reported that the film was scheduled to open on October 12, about three weeks before the November presidential election. After her column was published, however, media reports said that the release date had been postponed until December.

In an email to Reuters on Wednesday, Boal confirmed that the film is scheduled for release in December. He said it was currently in post-production.

He said there was no political undertone to either the film or the timing of its release.

"The film has no partisan agenda," Boal said.

"The suggestions otherwise are from people who are clueless about the film. This is about black ops operatives who carried out the secret hunt for UBL (bin Laden). It's not about the president.

"There's no actor running around playing Obama in our movie," he added.

The screenwriter's assurances are unlikely to quiet Obama critics. Tom Fitton, president of Judicial Watch, the conservative group which requested and obtained records of the filmmakers' dealings with administration officials, said he wanted more information.

"The trailer is sure to have a lot of fans in the Obama campaign. The pre-Election Day hype for the movie makes it all the more important to get the full truth about the secret and inappropriate access the Obama administration gave the filmmakers," Fitton said.

(Reporting by Mark Hosenball; editing by Jim Loney)

• A Permanent Economic Emergency