At least eight people have been shot in a mass shooting at Fort Pierce in Florida, according to reports.
Crowds of people had gathered to watch a car show in Illous Ellis Park to celebrate Martin Luther King Day before the incident occurred at around 5.20pm local time (11:20pm GMT).
Unconfirmed footage shared online showed people appearing to run for cover as gunshots ring out in the background.
Another video clip from the scene showed crowds of people dispersing and moving along the road in the aftermath.
One person is said to be in a critical condition following the shooting, while seven others are also being treated in hospital. Four others were left injured in the panic that followed the shooting, police said.
A car and bike show named "Streets on Lock" had been scheduled at the park between 2pm and 5pm local time with the shooting taking place after the event had finished, reports WPTV.
More than 1,000 people were estimated to have attended the event.
St. Lucie County Sheriff's Office chief deputy Brian Hester said an initial investigation suggested the shooting had arisen following a "disagreement of some sort between two parties", causing a number of innocent people to be caught up in the gunfire.
Describing the aftermath, Mr Hester told reporters: "It was mass chaos as you can imagine when shots rang out with, there were a thousand plus people here at the event, and as the shots rang out, people were just running in all directions"
The chief deputy also revealed that tips and evidence taken from the scene led investigators to believe multiple shooters were involved.
He went on to speak his sadness of the violence at a "celebration of someone who represented peace and equality", with the event marking Martin Luther King Day.
A heavy police presence has been witnessed at the scene in the hours since the shooting, with St. Lucie County Sheriff's office said to be following several leads.
A short message posted on the Facebook of the Sheriff's Office said an update would be provided "as more information becomes available".
