Multiple people are dead after a shooting at an outdoor mall in downtown Jacksonville, according to local authorities. It’s not clear where in the complex the shooting happened, but a bar in the mall was holding a Madden video game tournament at the time.

One suspect is dead at the scene, the Jacksonville Sheriff’s Office tweeted, and investigators are working to determine if there is a second suspect on the loose. The sheriff’s office added that “many” victims have been transported for medical treatment after the shooting at Jacksonville Landing, a waterfront complex along the St. Johns River.

Memorial Hospital in Jacksonville said it had received three patients from the scene, all of whom are stable. The extent of their injuries was not disclosed.

Video game company Electronic Arts tweeted that a shooting took place at a sanctioned Madden Championship Series competition. GLHF Game Bar, a bar in Jacksonville Landing, had posted on its Facebook page that it was holding a Madden tournament Sunday afternoon.

Videos posted to social media show what sounds like gunfire ringing out as competitors play video games.

Multiple members of the online gaming community stopped playing on the live-streaming service Twitch to react to reports of the shooting. “I’m not playing right now. This is too upsetting,” gamer WalkerCLE said.

Investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives are en route to the scene, and the FBI’s Jacksonville field office is assisting in the investigation. Florida Gov. Rick Scott has also offered state resources to assist in the investigation.