US director Oliver Stone defended the timing of his latest movie "World Trade Center" in Beijing on Wednesday, saying the "pain" of the 9/11 attacks needed to be expressed. 　

"It's a shame, but part of our life. Maybe there would be another movie about it (if I hadn't shot it). To see it can be painful, and you can cry in the movie, but pain and crying sometimes is good," the award-winning director told reporters. 　

"World Trade Center", starring Nicolas Cage, is based on the true story of two policemen who were trapped in the rubble of the Twin Towers in 2001 and supported each other for 12 hours before their rescue. 　　

Stone said he had tried to accurately portray the disaster, shooting a third of the film in New York, but using a Los Angeles set for the ruined Twin Towers and chaotic street scenes. He also persuaded witnesses to recall their experiences.

"It was a nightmare (to make the movie) because you want to be as realistic as possible, but you cannot really show the pain. It's too much. The audience would go screaming from the theater," Stone said. 　

The two policemen in the movie were among 20 people rescued from the rubble in which 2,749 people died. Stone said he selected them as the main characters because the story was coherent. 　　

"They were not only together, but cooperated with each other. They're maybe better stories than the others," he said. 　

Stone is known for his politically-themed films such as "JFK", "Nixon" and "Platoon", but he said "World Trade Center" had nothing to do with politics, but humanity and responsibility. 　　

"We have the true story now. We have a moment-by-moment, hour-by-hour account which we know is true. I'm still scarred and wounded, but the question should be told as quickly as possible." 　　

He told reporters the movie was a way to tell a big story through a narrow angle in which two people help each other and people help them. 　　

"World Trade Center" has reaped over 200 million U.S. dollars since its release in North America on Aug. 9, and is scheduled to make its release in China on Nov. 10.