At least four people are dead and many more injured after a mass shooting at a video game tournament in Jacksonville, Florida.

The gunman is among the 'multiple fatalities' as the horror was captured live on the internet, with social media livestreaming as the shooting began.

At least four people were dead and 11 injured, local media are reporting.

Horrifying livestream audio from the Madden NFL online gaming tournament captured the screams of players as the gunfire erupted at the Jacksonville Landing in Florida on Sunday afternoon.

— Jax Sheriff's Office (@JSOPIO) August 26, 2018

#BREAKING #Massshooting reported in #Jacksonville, #Florida, police say
.#US #shooting #ActiveShooter #Forsan_News pic.twitter.com/ltjz56YPA5

— Forsan News EN (@Fnews_english) August 26, 2018

The commentators could be heard going silent as the first gunshots were fired and people began screaming. The stream then cut out and a message appeared saying "controller disconnected".

Witnesses have said the shooter was a player who had just lost in the tournament.

One witness told CNN he saw the gunman shoot multiple people before killing hi

The shooting broke out during the Madden football online gaming tournament at Florida 's Jacksonville Landing. Image / WJXT

Multiple fatalities at the scene, many transported. #TheLandingMassShooting https://t.co/qBJvkaO7xT

— Jax Sheriff's Office (@JSOPIO) August 26, 2018

Authorities say it has occurred at the Jacksonville Landing, a popular downtown area filled with restaurants and bars and a shopping centre on Sunday afternoon local time.

The Jax Sheriff's office warned the public via Twitter to "Stay far away from the area. The area is not safe at this time. STAY AWAY".

They later added: "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."

Mass shooting at the Jacksonville Landing. Stay far away from the area. The area is not safe at this time. STAY AWAY #TheLandingMassShooting

— Jax Sheriff's Office (@JSOPIO) August 26, 2018

We can’t stress enough to stay away. Many blocks away. https://t.co/qBJvkaO7xT

— Jax Sheriff's Office (@JSOPIO) August 26, 2018

This mass shooting occurred during a Madden 19 tournament at the GLHF restaurant at Jacksonville Landing. Police are warning people to avoid area - gunman may not yet be in custody

— Steve Brusk (@stevebruskCNN) August 26, 2018

Fox News reported that several people on social media participating in the Madden NFL Championship Series reported hearing gunshots. The event was being livestreamed and showed players reacting as gunshots were heard in the background.

Just saw someone on a stretcher loaded into an ambulance at this intersection. This is near the #Jacksonville Landing where @ActionNewsJax is told there has been a shooting pic.twitter.com/AY0GwTfTx7

— Brittney Donovan (@brittneyANjax) August 26, 2018

The commentators could be heard going silent as the first gunshots were fired and people began screaming. The stream then cut out and a message appeared saying 'controller disconnected'.

The public are warned to keep away from Jacksonville Landing.

One of the gamers, Drini Gjoka, said he was shot in the hand.

"The tourney just got shot up. I'm leaving and never coming back. I am literally so lucky. The bullet hit my thumb. Worst day of my life," he tweeted.

I am literally so lucky. The bullet hit my thumb

— Drini Gjoka (@YoungDrini) August 26, 2018

"I will never take anything for granted ever again. Life can be cut short in a second."

A reporter from Fox-affiliate CBS47/FOX30, Brittney Donovan, said that at least one person was seen being loaded onto a stretcher and into an ambulance.

BREAKING ALERT: Witnesses are saying shooter was a disgruntled gamer who was upset at losing the tournament; went home and brought back a semi-automatic. #TheLandingMassShooting

— TheAnonJournal (@TAPAlerts) August 26, 2018

BREAKING ALERT: Witnesses are saying shooter was a disgruntled gamer who was upset at losing the tournament; went home and brought back a semi-automatic. #TheLandingMassShooting

— TheAnonJournal (@TAPAlerts) August 26, 2018

Madden NFL 19 is a video game based on the NFL that's developed and published by EA Sports.

- Additional reporting Daily Mail