"Contagion," an action-thriller about preventing the spread of a deadly virus, had its crew and military tanks stationed around Civic Center Plaza this afternoon along with hundreds of extras wearing pandemic flu masks.
Production assistants declined to comment on the scene they were filming.
"The public needs to take a giant step back," a crew member shouted. "We are using the entire square. I can see you behind that truck!"
About 2,000 local men and women of all sizes and ethnicities were cast in background roles for about 10 days of filming in San Francisco.
"The movie is all about an infectious disease and Center for Disease Control doctors are trying to track down and isolate it," said Rich King, who is in charge of casting the extras.
King said filming will take in several places in the city, including an undisclosed stadium, a coffee shop, and a location near Chinatown.
The movie, based on medical novelist Dr. Robin Cook's book of the same name, is tentatively planned for an October release, and will also feature Gwyneth Paltrow and Laurence Fishburne.
The book focuses on a rare strain of influenza that strikes the young, old and the innocent.
Filming has already taken place in Chicago, Atlanta, and Hong Kong.
King said hired actors who are Screen Actors Guild members are being paid $139 daily for their work and non-union members make $64 each day.