Update I

There is no longer a threat to people in the area.

NBC News is reporting that the female suspect is deceased on scene, a firearm was recovered, and the number of victims is unknown.

NBC News: Multiple law enforcement officials say that the suspected shooter at YouTube is a woman and that she is deceased. Reported w/ @anblanx

— Tom Winter (@Tom_Winter) April 3, 2018

NBC is reporting female suspect deceased at the scene with an unknown number of victims

— Ben Jacobs (@Bencjacobs) April 3, 2018

Update II

At 12:46 pm, 911 calls were received about gunshots on the YouTube campus. Law enforcement arrived on scene at 12:48 pm. There is one female deceased on scene. It has yet to be confirmed if the deceased individual is the shooter, but is believed to be the suspect. The suspected shooter died from a self-inflicted gunshot wound. Four other victims were transported to nearby hospitals, and one is said to be in critical condition.

** Original Post **

There are reports of an active shooter at YouTube Headquarters in San Bruno, California. YouTube employees have evacuated the building, and hospitals are receiving employees who sustained gunshot wounds.

The ATF San Francisco Field Division is responding to a reported shooting at YouTube headquarters in San Bruno, Calif. pic.twitter.com/l7XabZ5FpI

— ATF HQ (@ATFHQ) April 3, 2018

YOUTUBE SHOOTING: Stanford Health Care says it is treating 4-5 patients from shooting; no word on conditions; Zuckerberg San Francisco General Hospital also says it is receiving patients https://t.co/9LsxgEdOdD pic.twitter.com/E9wKMg82jA

— ABC7 Eyewitness News (@ABC7) April 3, 2018

A YouTube employee tweeted out his experience as shots rang out.

Active shooter at YouTube HQ. Heard shots and saw people running while at my desk. Now barricaded inside a room with coworkers.

— Vadim Lavrusik (@Lavrusik) April 3, 2018

According to a CBS News anchor, an eyewitness said the shooter started at a party on the YouTube campus.

CBSN Now: Eyewitness account from YouTube HQ. Man says this started at a party oncampus.

— ReenaNinan (@reenaninan) April 3, 2018

Some local stations are reporting information about the potential shooter, but the reports have yet to be confirmed.

JUST IN: Law enforcement sources tell the Bay Area ABC affiliate "the shooter is a white, adult female wearing a dark top and head scarf." https://t.co/BxZVhzHlxz

— KSAT 12 (@ksatnews) April 3, 2018

WATCH LIVE: Shooter at #YouTube in #SanBruno believed to be white female adult wearing dark top and headscarf. https://t.co/U5RwzFfya6 pic.twitter.com/NFG8MP7MdZ

— ABC7 News (@abc7newsbayarea) April 3, 2018

This article will be updated as more information is released.