Police and federal officials have responded to reports of a shooting Tuesday at YouTube headquarters in Northern California.
  
Police in the city of San Bruno said there was an active shooter but could not provide more information. Multiple 911 calls reported gunfire, and police and fire officials have responded, City Manager Connie Jackson said.
  
Television news footage showed people leaving the building in a line, holding their arms in the air for police to inspect as they were leaving the building. Officers patted down people grouped outside, and police vehicles surrounded the area.

  
Google, which owns the world's biggest online video website, posted on Twitter that the company is coordinating with authorities. The Bureau of Alcohol, Tobacco, Firearms and Explosives says it's also responding to the shooting at YouTube's suburban campus.
  
YouTube employee Vadim Lavrusik posted on Twitter that he heard gunshots and saw people running. He said he was barricaded in a room with his co-workers before being safely evacuated.
  
Will Hudson said his friend who works for YouTube texted him about the shooter.
  
"I think there might be a shooter in my building," read one text. "The fire alarm went off so we started to evacuate and then people (started) running saying there was a shooter."

  
Hudson said his friend has made it safely back to San Francisco and is in contact with his family. Hudson said he's become accustomed to hearing about such violence but has never been so close to it before.
  
"It just feels strange. It feels like it could really be anyone. That's really the strangeness of it," he said.
  
Calls and emails to YouTube representatives were not immediately returned.