'Active Shooter' at YouTube HQ in Northern California

Police in Northern California say they are responding to an incident involving an "active shooter" at YouTube headquarters.

Gunshots were reported at the company's campus in San Bruno, south of San Francisco.

Ambulances are at the scene and authorities have warned the public to stay out of the area.

Google, which owns YouTube, has said it is investigating a possible "gunfire incident".

Unconfirmed reports from local media say the shooter is a woman.

NEW: Police confirm to @NBCNews the female suspect in the shooting at Youtube's headquarters has died at the scene. pic.twitter.com/IysaJAuOZN — MSNBC (@MSNBC) April 3, 2018

Zuckerberg San Francisco General Hospital has said it is treating patients from the incident. No details were provided on their condition.

Some 1,700 people work at the YouTube HQ. Google said it was "coordinating with authorities" and would provide information as it becomes available.

Images broadcast on local TV stations showed employees leaving with their hands raised. Other footage appeared to show evacuees forming a queue before being individually frisked by police.

YouTube product manager Todd Sherman tweeted that people fled the building in panic.

We were sitting in a meeting and then we heard people running because it was rumbling the floor. First thought was earthquake. https://t.co/gmolQmRXm1 — Todd Sherman (@tdd) April 3, 2018

Another employee, Vadim Lavrusik, initially tweeted he was barricaded in a room with other staff. He later said he had been evacuated.

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