The tournament was attended by professional players from around the world.
Hours after the mass shooting was police said the suspect, who died in the incident, succumbed to a self-inflicted injury. The shooting occurred at the Maddeb NFL 19 competition at Jacksonville Landing.
The place, as per reports, is a popular waterfront shopping and dining area in the heart of downtown Jacksonville in Florids.
The tournament was being hosted by the restaurant Chicago Pizza.
As per reports, the authorities said they received a 911 emergency call at 11:24 pm in Sunday afternoon regarding shooting at the restaurant.
The gunman is believed to be 24 years old, belonging from Baltimore, the officers said reportedly.
According to reports, 11 people were injured in the shootout, Nine of them had gunshot wounds while two were injured while they were trying to flee the scene.
Sheriff Mike Williams said “Our investigation has revealed that the suspect had come to attend the gaming competition. However, we are yet to confirm his name and other details. We have also not yet established the motive behind the shooting. A search of his vehicle is being done," he said.