SAN FRANCISCO, April 3 (Xinhua) -- Police in San Bruno in the U.S. state of California on Tuesday warned residents to stay away from the headquarters of the world's largest video sharing network Youtube, where an active shooting was reported.

"Police activity at 901 Cherry Ave, please stay out of the area," San Bruno Police tweeted.

People near the area reported hearing shots fired, police activity and lockdown procedures, and police radio said casualties were being taken to local hospital.

"Active shooter at YouTube HQ. Heard shots and saw people running while at my desk. Now barricaded inside a room with coworkers," wrote Twitter user Vadim Lavrusik. Enditem