ACKSONVILLE, Fla. (AP) — Gunfire broke out Sunday at a Florida mall that was hosting a video game tournament, killing multiple people and sending many others to hospitals, authorities said.

One suspect was dead at the scene at the Jacksonville Landing, a collection of restaurants and shops along the St. Johns River. It was unknown if other suspects were involved, the Jacksonville Sherriff’s Office reported.

The sheriff’s office used Twitter and Facebook to warn people to stay far away. “The area is not safe at this time,” the office said.

“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 office said on Twitter.

Authorities did not provide any other information.

The GLHF Game Bar at the Landing was hosting a Madden 19 video game tournament at the time of the shooting.

After the shooting, police barricaded a three-block radius around the mall. Officers and Coast Guard boats patrolled the nearby river. Many ambulances could be seen in the area, but the mall area appeared empty of all but law enforcement. Police also took up positions on a bridge overlooking the river.

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.