Berlin - Tom Cruise, who plays the lead role in the film Valkyrie about a 1944 attempt to kill Hitler, spoke ahead of the film's European launch Tuesday of the duty he felt to accurately portray a little-known aspect of Nazi Germany.

The Hollywood co-production is based on the plot carried out on July 20, 1944, when the aristocratic German officer Claus Schenk von Stauffenberg tried to kill Hitler by placing explosives under his table.

"This was a very challenging film to make and certainly the whole time we carried a huge burden of the responsibility of the history," Cruise said ahead of Tuesday's European premiere in Berlin.

The star added that the cast and crew wanted to "represent the spirit of the resistance and the history in the most accurate way," whilst "being able to deliver a piece of entertainment to the world."

Intended as a "thriller" rather than a documentary re-enactment of events, Valkyrie is the first international big-budget production to focus on the role of the German resistance.

The film's director, Chris McQuarry, said "my personal determination was to smash a stereotype" of Germany that has developed in the United States.

Valkyrie first opened in the US in December where, despite mixed reviews, it has brought in box office revenues of nearly 72 million dollars to date.

The production has drawn criticism for a lack of depth and for simplifying the motives behind the plot.

Writing in the Washington Post, Phillip Kennicott says the film fails to portray the officer's early years as a soldier loyal to Hitler. Stauffenberg, he writes, "was not a committed anti-Nazi until very late in the game."

On the other hand, Stauffenberg biographer Peter Hoffmann commends the film for remaining true to the facts.

He said he believes it marks a turning point in people's understanding of the German resistance, by showing that "not all officers were followers of Hitler, indeed some may even have been anti-Nazi."

Stauffenberg's great-nephew, Franz von Stauffenberg, says the film has been made into a "good thriller," but is critical of Cruise's acting, saying he lacks expression, appears stiff and shows none of his great-uncle's characteristic humour.

"Tom Cruise seems terribly cautious, almost as if he were afraid of playing the role," he told the German Welt am Sonntag newspaper.

There was an initial German outcry at the casting of Cruise, a prominent member of Scientology, in the lead role. The organization's activities are closely monitored in Germany.

In addition, the German authorities initially refused permission to film at the historically sensitive Bendler Block in Berlin, where von Stauffenberg was executed on the day of the failed coup. The producers eventually obtained permission to use the location, on the condition that due respect was shown to the resistance leaders, and that it was made amply clear in the film that democracy finally triumphed in Germany.

Speaking ahead of the opening night, German Culture Minister Bernd Neumann said Monday of the US-German co-production, "the film successfully introduces international audiences to a chapter of German history which is little known abroad."

Neumann said the film, produced at the Babelsberg studios near Berlin, was proof of Germany's growing role as a film location.

The release of Valkyrie has unleashed a debate in Germany about the accurate representation of the historical facts, as well as von Stauffenberg's character and the true motives behind the plot.

The film's subject has been historically sensitive in postwar Germany. After 1945, it took several decades for Germans to recognize the role of the resistance movement. In some instances, families had to wait until 1998 to see Nazi verdicts of treason overturned. dpa