Police and the FBI are responding to "an active shooter" at Alphabet Inc.'s YouTube headquarters in San Bruno, California.

The San Mateo County (California) Sheriff's confirmed that an active shooter situation has taken place on the campus that is located just north of Silicon Valley in California.

Law enforcement authorities say there are injuries at the site.

Here’s what we know about the YouTube headquarters:

  • The building is located on Cherry Avenue in San Bruno.
  • About 1,700 people work at the campus.
  • A series of buildings make up 1.1-million square feet of workspace.
  • Employees tweeted Tuesday afternoon that shots were heard at the offices shortly after 1 p.m. PT
  • The building features open areas and communal workspaces.
  • YouTube is the largest private employer in the area.
  • The facilities are in San Bruno – a city about 11 miles south of downtown San Francisco. It is near the San Francisco International Airport.
  • There is a Google employee facility nearby as well as a Walmart e-commerce office.