Active shooter at YouTube HQ in San Bruno

An active shooting at YouTube’s headquarters in San Bruno, Calif., left at least one person dead and several others injured Tuesday, law enforcement sources told The Times.

Lisa Kim, a spokeswoman for Standford Medical Center, said at least four patients from the shooting were expected to be admitted at the medical center.

“We do not know their conditions,” she said.

Brent Andrew, a spokesman for Zuckerberg San Francisco General Hospital and Trauma Center, said the hospital had “received several patients” and was expecting more.

Several YouTube employees sent tweets Tuesday afternoon, saying people were racing out of the company’s Cherry Avenue offices shortly after 1 p.m.

At least two people were reportedly struck by gunfire, according to a law enforcement source who was not authorized to speak publicly about the incident. The shooter was described as a woman. So far authorities do not believe this was an act of terrorism and appears instead to have been a case of domestic or workplace violence — although the investigation has just begun.

Witnesses in the area said they saw dozens of firefighters and police officers descending on the area. Other witnesses said they saw police holding rifles and other weapons.