More than a dozen people have been shot and four are reportedly dead after a gunman opened fire during the live online broadcasting of a video game contest in Florida.
Video of the incident in Jacksonville showed a red laser dot dance across the chest of one of two young men playing the American football game moments before the sound of gunshots popped. The video of the players then went dead.
On the subsequent audio portion of the recording one man could be heard shouting: "What the f*** are you shooting with?"
As the sound of gunfire continued, one person wrote in the comment stream: "Run run run run run pass run run run."
On Sunday afternoon, as CNN said four people including the gunman were dead, Jacksonville police confirmed "multiple casualties" had been found deceased at the scene of the shooting, a regional qualifier for the Madden 19 online game tournament being held at the GLHF Game Bar inside a Chicago Pizza restaurant.
"We have no outstanding suspects at this time," Jacksonville Sheriff Mike Williams said, while declining to give a specific number of victims. "We have one suspect in this case. He is deceased at the scene."
Mr Williams said the suspect was a white male but refused to immediately provide further information about his identity or motive.
The Los Angeles Times quoted one of the competitors, Steven Javaruski, as saying the shooter was someone who had previously lost a game.
He said the shooter "targeted a few people" and shot at least five victims before killing himself.
Another individual taking part in the tournament in the city's Jacksonville Landing waterfront district, Drini Gjoka, said he was shot in the thumb when the incident happened around 2pm.
"Worst day of my life," Mr Gjoka wrote on Twitter.
"I will never take anything for granted ever again. Life can be cut short in a second."
Police initially confirmed a mass shooting on social media.
"Mass shooting at the Jacksonville Landing. Stay far away from the area. The area is not safe at this time," the Jacksonville Sheriff's Department tweeted. "We can't stress enough to stay away. Many blocks away."
A few minutes later the police said there were multiple fatalities at the location and "many" other victims had been transported away for treatment.
"One suspect is dead at the scene, unknown at this time if we have a second suspect. Searches are being conducted," it added.
On an online stream of the event posted to the website Twitch, which is owned by Amazon, people could he heard shouting against the backdrop of rapid gunfire.