SAN BRUNO, Calif. (AP) — Police in Northern California are responding to reports of a shooting at YouTube headquarters in the city of San Bruno.

City Manager Connie Jackson says there have been multiple 911 calls reporting a shooting and that police and fire officials have responded.

TV helicopter video shows officers patting down people grouped outside a building and police vehicles surrounding the area. San Bruno police said they could not provide more information.

The world's biggest online video website is located on a suburban campus.

Calls and emails to YouTube representatives were not immediately returned Tuesday afternoon.