JACKSONVILLE, Florida: A gunman opened fire Sunday at an online video game tournament as it was being livestreamed from a Florida mall, killing two people and then fatally shooting himself in an attack that sent several others to hospitals, authorities said.

Jacksonville Sheriff Mike Williams said authorities believe 24-year-old David Katz of Baltimore carried out the attack using at least one handgun at the Jacksonville Landing, a collection of restaurants and shops along the St. Johns River. He said the man died from a self-inflicted gunshot, adding authorities were still making final confirmation of his identity with the FBI assisting them in Baltimore.

Nine other people were wounded by gunfire and all were in stable condition Sunday evening after going to hospitals, Williams said. He added that two others were hurt as people sought to flee the gunfire in the panic and chaos that ensued.

Katz was in Jacksonville for the "Madden NFL 19" video game tournament, authorities said. The games maker, EA Sports, lists a David Katz as a 2017 championship winner.

Thee competition was held in a gaming bar that shares space with a pizzeria. Viewers could watch the games online and see the players.

The sheriff’s office used Twitter and Facebook to warn people to stay far away and to ask anyone who was hiding to call 911.

“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,” the sheriff’s office said via Twitter.

**IMPORTANT** If you are hiding in The Landing. Call 911 so we can get to you. #TheLandingMassShooting https://t.co/qBJvkaO7xT

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

Defeated competitor

According to the LA Times, quoting player Steven “Steveyj” Javaruski, a professional Madden player for Noble eSports, the shooter was a gamer who had been competing and lost.

Madden is a hugely popular multi-player video game based on the National Football League.

The tournament at The Landing entertainment and shopping complex — a regional qualifier for finals in Las Vegas with a $25,000 prize — was being held at the GLHF Game Bar.

Investigators were looking into online video that appeared to capture the scene right before the shooting began, Williams said. A red dot that appears to be a laser pointer is visible on the chest of a player seconds before the first of about a dozen gunshots rings out.

Marquis Williams, 28, and his girlfriend, Taylor Poindexter, 26, both from Chicago, were ordering pizza at the bar when they heard the first shot.

"Initially we thought it was a balloon popping, but there weren't any balloons in the room," said Williams, who had taken part in the tournament earlier. "Then we heard repeat shots and we took off running." Williams added: "The first shot everybody just turned and looked. After the second, third and fourth shots, everybody took off and ran for the exits."

Taylor Poindexter, an aspiring gamer, said she had hoped to gain some experience at the tournament. She said she never saw the face of the man who was shooting. But she recalled, "We did see him with two hands on a gun walking back just popping rounds."

He said the two ran to a nearby restaurant where workers were waving people in, hiding in a bathroom until police arrived.

Jason Lake, the founder and CEO of compLexity, a company that owns professional e-sports teams, said on Twitter that one of his players, 19-year-old Drini Gjoka, was shot in the thumb.

Gjoka tweeted: "The tourney just got shot up. Im leavinng and never coming back." Then: "I am literally so lucky. The bullet hit my thumb. Worst day of my life."

On Sunday evening, an FBI official in Baltimore confirmed that its agents were searching the family home of the man authorities said they believe was behind the attack. An FBI spokesman, Dave Fitz, said agents had gone to the house of the man's father in Baltimore. He declined to release specifics, citing the ongoing investigation.

In Washington, White House spokeswoman Sarah Huckabee Sanders said President Donald Trump had been briefed on the attack and the White House was monitoring the situation.

The Jacksonville Landing, in the heart of the city's downtown, also hosts concerts and other entertainment. It was the site of a Trump rally in 2015, early in his campaign for the White House.

The sheriff's office used Twitter and Facebook immediately after the shooting to warn people to stay far away and to ask anyone who was hiding to call 911. Police also barricaded a three-block radius around the mall and police boats patrolled the nearby river. Police also took up positions on a bridge overlooking the river.

Land of mass shootings

Survivors of the high school shooting in Parkland, Florida, in February, expressed sorrow at news of another mass shooting in the state.

“Once again, my heart hurts and all of me is so angry. We cannot accept this as our reality,” Delaney Tarr, one of the organizers of the student-led March for Our Lives movement, tweeted.

Florida has suffered multiple shootings in recent years: 49 were killed in a June 2016 attack on a gay nightclub, while 17 were killed at Marjory Stoneman Douglas High School earlier this year.

Florida Senator Marco Rubio said that the FBI and Bureau of Alcohol, Tobacco, Firearms and Explosives were investigating Sunday’s shooting.

Florida Governor Rick Scott, meanwhile, said he had offered state support in the aftermath.

White House press secretary Sarah Sanders confirmed President Donald Trump had been briefed on the incident.

“We are monitoring the situation,” she said.