WARNING: DISTRESSING CONTENT
Two people were killed and 11 others wounded when a video game tournament competitor went on a shooting rampage before turning the gun on himself in the northern Florida city of Jacksonville.
David Katz, 24, has been identified as the suspect shooter at an online gaming tournament in Florida that was partially captured on a horrifying livestream.
Katz carried out his shooting rampage at the Jacksonville Landing complex at around 1.34pm on Sunday (local time), police said.
Jacksonville Sheriff Mike Williams confirmed that Katz is from Baltimore and had travelled to Jacksonville for the tournament.
He is also known by the gamer monikers 'Ravenschamp' and 'bread'.
Katz was armed with a semi-automatic and his car was seized by police near the scene.
Williams could not confirm if Katz knew any of the victims.
According to Steven "Steveyj" Javaruski, one of the competitors, the shooter was a gamer who was competing in the tournament and lost.
The shooter "targeted a few people" and shot at least five victims before killing himself, Javaruski told The Los Angeles Times in a direct message on Twitter.
He later tweeted police escorted him out of the venue.
Sheriff Williams said federal authorities raided a house at South Baltimore as part of the investigation into the shooting.
He appealed for anyone with videos or information of the incident to contact the Sheriff's Office.
Earlier dozens of ambulances and police cars flooded into The Jacksonville Landing within two minutes of a call, a waterfront dining, entertainment and shopping site in the city's downtown, after several shots rang out on a sunny Sunday afternoon (local time).
The shooting took place during a regional qualifier for the Madden 19 online game tournament at the GLHF Game Bar inside a Chicago Pizza restaurant, according to the venue's website.
Distressing live stream footage, posted on Twitter, shows two people, smiling with headphones on and playing the Madden 19 American football game before screaming and gunshots can be heard ringing out in the background.
The numerous loud gunshots suddenly interrupt the stream and disrupting the video connection — leaving a "controller disconnected" warning as the players fled.
Audio of the shooting was being broadcast live as the tournament was underway, with several loud gunshots suddenly interrupting the stream and disrupting the video connection.
A red dot that appeared to be a laser pointer was visible on the chest of a player seconds before the first of a dozen gunshots rang out.
After several gunshots, people scream and one person cried out, "Oh f---, what'd he shoot me with?" The stream did not show the shooting.
Investigators were looking into the online video.
Florida authorities say they've finished clearing the scene.
The sheriff's office said many people were transported to hospital, and its deputies found many others hiding in locked areas at The Landing.
Six victims were taken to Jacksonville's UF Health Hospital, five of them in stable condition and one in serious condition, hospital staff said.
A spokesman for Jacksonville's Memorial Hospital said it was treating three victims, all of whom were in stable condition.
Sheriff Williams said of the injured nine suffered gunshot wounds and two were hurt while fleeing.
Earlier the Jax Sheriff's Office said they were finding people hiding in the area and urged them to stay calm.
The event was the Southeastern Qualifier for the Madden NFL Championship Series for Madden NFL 19, according to the GLHF Game Bar's Facebook page.
"This is your chance to earn your spot in the first Major's Live Finals happening in October 2018. Don't hesitate to secure your spot," the post read in part.
One of the competitors, Drini Gjoka, was grazed by a bullet.
Florida Governor Rick Scott said he had offered to provide local authorities with any state resources they might need.
White House Press Secretary Sarah Huckabee Sanders said US President Donald Trump has been briefed but we are yet to hear from the president.
Mr Trump's daughter, Ivanka, has tweeted her condolences.
The Florida shooting occurs amid a debate about US gun laws that was given fresh impetus by the massacre in February of 17 people at a high school in Parkland, Florida.
Two years ago a gunman killed 49 people at the Pulse nightclub in Orlando.
It didn't take long for some Democratic candidates for governor to issue statements on the shooting.
Ahead of Tuesday's primary election, in which voters will pick the Republican and Democratic nominees to replace outgoing Republican Gov. Rick Scott, former US Rep.
Gwen Graham sent an email to supporters that said the only way to end mass shootings is to "vote out the politicians complicit in this cycle of death."
Florida Senator Bill Nelson expressed "shock" and "outrage".
Former Miami Beach Mayor Philip Levine also released a statement saying, "I am horrified and I am furious" and that it's time for new leaders.
Video game manufacturer Electronic Arts tweeted, "This is a horrible situation, and our deepest sympathies go out to all involved."
The NFL released an official statement in support of their sporting partners.
Former NFL quarterback and current professional baseball outfielder in the New York Mets Tim Tebow also tweeted his support.
The Jacksonville Landing, in the heart of the city's downtown, hosts concerts and other entertainment, has a busy food court and a host of bars and restaurants. President Donald Trump held a rally there in October 2015 early in his campaign for the White House.
Madden 19's developers Electronic Arts has taken to Twitter to offer its "deepest sympathies" to those involved in the shooting and said it was working with police to aid the investigation.
Florida has been the site of other recent mass shootings — the February massacre of 17 people at Marjory Stoneman Douglas High School in Parkland, and the fatal shooting of 49 people at the Pulse nightclub in Orlando two years ago.