Police officers swarmed YouTube's headquarters in northern California on Tuesday after reports of an Active gunman.

San Bruno police say they "are responding to an active shooter" and cautioned people to stay away from the building, which is on Cherry Avenue, about 11 miles south of San Francisco. 

Photos on social media showed dozens of people being escorted by law enforcement out of the building with their hands up. Employees of the company say they Heard what sounded like shots and took cover. 

After being escorted out of the building, helicopter footage showed those inside being patted down by police.