Graphic warning: Audio of Florida mass shooting captured on livestream

At least a dozen shots could be heard - followed by a horrific chorus of terrified screams - as a gunman opened fire this morning at an online video game tournament that was being livestreamed from a US mall.

Three people are dead, including the shooter, and 11 hurt after the incident in Jacksonville. 

The livestream was showing gamers playing NFL-themed video game Madden 19 when the shots began to ring out. Play then stopped as the controller disconnected – cutting off the view of the gamers themselves. But audio continued to record the rampage, and the resulting pleas for help.

Police say at least 11 others are injured after the incident at a games bar in Jacksonville. Source: 1 NEWS

Sheriff Mike Williams said authorities had yet to identify the suspect who attacked the tournament, which was held in a gaming bar that shares space with a pizzeria. Investigators are looking into the online footage, he said.

A red dot that appears to be a laser pointer is visible on the chest of a player seconds before the first of a dozen gunshots rings out.

Early reports say the shooting took place during a Madden 19 tournament in Jacksonville. Source: Breakfast

The sheriff's office used Twitter and Facebook to warn people to stay far away and to ask anyone who was hiding to call 911.

"We are finding many people hiding in locked areas at The Landing. We ask you to stay calm, stay where you are hiding. SWAT is doing a methodical search inside The Landing. We will get to you. Please don't come running out," the sheriff's office said via Twitter.

The sheriff's office did not provide any other information, but also warned reporters to stay away from the area.

Police barricaded a three-block radius around the mall. Officers and Coast Guard boats patrolled the nearby river. Many ambulances could be seen in the area, but the mall area appeared empty of all but law enforcement. Police also took up positions on a bridge overlooking the river.

The Jacksonville Landing, in the heart of the city's downtown, also hosts concerts and other entertainment. It was the site of a Donald Trump rally in 2015, early in his campaign for the White House.