This from New York 1:

The mayor’s office of film, theatre and broadcasting is warning
residents that live around the Brooklyn Bridge not to be alarmed this
week when military vehicles, army helicopters and a flood of people
swarm the area for a film shoot.

Officials say a scene from the movie "I am Legend" will be filmed near the span.

The office says Army and Coast Guard helicopters, mock police and
military vehicles, and more than a thousand extras will be used for the
film’s evacuation scene.

The action is set to get underway at around 4 p.m. Tuesday and continue on weekdays through the rest of the month.