UPDATE: At least three people were wounded and the suspected shooter, a woman, was found dead on the campus of the YouTube headquarters, San Bruno, California, Police Chief Ed Barberini told reporters Tuesday.
The chief said the dead woman had an apparent self-inflicted gunshot wound.
A spokesman for Zuckerberg San Francisco General Hospital told CNN affiliate KGO the facility received three patients. One 36-year-old man was in critical condition, one 32-year-old woman was in serious condition and one 27-year-old woman was in fair condition
(CNN) - The city of San Bruno received multiple 911 calls from YouTube headquarters, with callers reporting shots fired, San Bruno City Manager Connie Jackson tells CNN.
The city has responded with a "massive police and fire response."
San Bruno police say on Twitter: "We are responding to an active shooter. Please stay away from Cherry Ave & Bay Hill Drive."
One YouTube employee said people were trying to get out of the building "as fast as they could."
She said she was on a conference call and her boss, who heard shots, told her at least one person was shot on the patio where people eat.
"We were all suddenly aware of a lot of noises, of sounds, people running outside of the room where she was. And people screaming," said the employee, who was in a building down the street.
Overhead video from a CNN affiliate showed a heavy police presence outside the YouTube building. A crowd of people gathered outside the building and, one by one, were frisked and patted down by officers. Several roadways near the building were closed to traffic.
The Bureau of Alcohol, Tobacco, Firearms and Explosives will help investigate the incident, according to the agency's San Francisco office.
This is a developing story. Stay with News 18 for the latest.