Three people are dead after a fatal shooting during a video game tournament that was streamed live on Sunday in Jacksonville, Florida.

Jacksonville police Sheriff Mike Williams told reporters on Monday morning (AEST) nine other people suffered gunshot wounds while two others were injured fleeing the area.

The shooting occurred at the Jacksonville Landing complex during a Madden 19 tournament at the GLHF Game Bar inside a Chicago Pizza restaurant.

Mr Williams identified the gunman as 24-year-old David Katz, who took his own life inside Chicago Pizza after the shooting.

Katz had competed in the online gaming competition and used at least one handgun during the shooting, the sheriff said.

The Madden event was played live on the website Twitch and several loud gunshots could be heard over the stream as the game abruptly stops.

Watch the Madden 19 stream below

(warning: disturbing audio):

https://www.youtube.com/watch?v=VzfK-ir1Zt8

Reports suggest the shooting occurred after Katz was eliminated from the competition, but is yet to be confirmed by authorities.

At least three of the living victims were transported to hospital with at least one gunshot wound while three were shot more than once.

Eight of the nine victims are said to be in a stable condition, while one is in serious condition with wounds to the chest, Mr Williams said.

Complexity Gaming team posted that one of its players, Young Drini, was grazed on the hand in the shooting, but was safe.

“I am literally so lucky. The bullet hit my thumb.” Mr Drini said in a separate post.

Ryan Alemon, who travelled from Texas to participate in the tournament, said he ducked down and ran toward the restroom when he heard the gunshots, hiding there for about 10 minutes before running from the venue.

Jacksonville Landing is an open-air marketplace featuring stores, bars and restaurants in the centre of Jacksonville, Florida.

Malik Brunson was at a nearby Hooters restaurant when the shooting occurred.

“All I heard was he got a gun and the shooting started,” Mr Brunson told CNN.

“One of the men ran into Hooters with the shot wounds, they locked us in the restaurant,” he was quoted as saying.

US President Donald Trump has been briefed on the situation, White House press secretary Sarah Huckabee Sanders said.

Federal law enforcement officials were monitoring the situation, with the Bureau of Alcohol, Tobacco, Firearms and Explosives responding to the scene.