A crash caused by a truck driver at the start of a Pride parade in South Florida on Sunday (20 June) has killed one spectator and injured others, according to authorities.

Dean Trantalis, Ford Lauderdale mayor, said the pickup truck driver was part of the Wilton Manors Stonewall Pride parade and accelerated when he was told he was next, striking Pride-goers in the process. One man was killed while others were injured.

“After striking the pedestrians, the driver continued across all lanes of traffic, ultimately crashing into the fence of a business on the west side of the street,” said police.

In a statement posted to Facebook, Trantalis recalled: “It terrorised me and all around me. I reported what I saw to law enforcement and had strong concerns about what transpired – concerns for the safety of my community. I feared it could be intentional based on what I saw from mere feet way.”

Although Trantalis initially believed it was deliberate, the president of the Fort Lauderdale Gay Men’s Chorus, Justin Knight, called it a “tragic attack” and said it wasn’t, to his knowledge, “an attack on the LGBTQ community”.

The suspect wore a Gay Men’s Chorus logo on his t-shirt, and Knight told local media he was “part of the Chorus Family”.

Trantalis said the suspect’s vehicle was in close proximity to Debbie Wasserman Shultz, Democratic US representative. In photos and videos from the scene, Wasserman Schultz could be seen in tears in a convertible.

“The parade had just begun and we saw people lining up and ready to move and all of a sudden this white pickup truck dashed right through the crowd, barely missing congresswoman Wasserman Schultz’s car by inches and smashed through a gate,” he said.

Wasserman Schultz said she was safe but “deeply shaken and devastated that a life was lost,” adding: “I am so heartbroken by what took place at this celebration. May the memory of the life lost be for a blessing.”

Ali Adamson, Fort Lauderdale police detective, originally said authorities were investigating “all possibilities” and didn’t clarify whether they thought the attack was deliberate.

Christina Currie, one of the parade’s spectators, also believed it was pre-meditated. She told the South Florida SunSentinel: “All of a sudden there was a loud revving of a truck and a crash through a fence… It was definitely an intentional act right across the lanes of traffic.”

Gregory Tony, Broward Country sheriff, added: “Though authorities are still gathering information, we know two individuals marching to celebrate inclusion and equality were struck by a vehicle. This tragedy took place within feet of me and my team, and we are devastated having witnessed this horrific incident.”

On Sunday, the FBI said the crash was “not a criminal act directed at anyone”.

In his statement, Trantalis continued to say that “a picture is emerging of an accident in which a truck careened out of control”.

“As a result, one man died, two others were injured and the lives of two members of Congress were at risk,” he said. “My heart breaks for all impacted by this tragedy.”

According to Fort Lauderdale police, the 77-year-old driver has “ailments” that prevent him from walking. There was also no signs that he consumed drugs or alcohol before the incident.