"It's the true story of two New York Port Authority policemen who were trapped in the rubble, their wives and the children and the incredible, almost improbable rescue efforts that went on to rescue them," Stone said.
"The truth must exist in some way to confront power and extremism," the 59-year-old added.
Based on the clip, which follows the policemen as they go about their normal lives before joining the rescue effort after the towers are hit, "World Trade Center" does not appear to delve into conspiracies like his "JFK," about the assassination of John F. Kennedy.
The movie stars Nicolas Cage as the leader of the policemen who are trapped inside the building and must be saved.
The footage ended as the buildings came down, and all the audiences can see were Cage's eyes in the dark.
The full movie is due to be released in the United States in August, not long before the fifth anniversary of the attacks.
It comes several months after Paul Greengrass's "United 93," a film that seeks to reconstruct events on the hijacked plane which plowed into a field in Pennsylvania after three others had hit the World Trade Center and the Pentagon.
When the trailer for that film was shown, audience complaints prompted one New York City cinema to pull the advertisement off its screens.