Shots were fired as crowds were gathered for the Lone Star Rally in a historic district known as The Strand around 11 p.m. local time, Galveston Police Department spokesperson Kurt Koopmann told CNN.

All five people who were shot were taken to an area trauma center for treatment, Koopmann said.

“One person of interest has been detained, but not charged at this time,” Koopmann said.

He said the matter is currently under investigation.

The cause of the attack is still not clear.

The rally had already drawn a heavy law enforcement presence to the area, which allowed first responders to react quickly, Koopmann said.

Meanwhile, the Facebook page of the Galveston Police said: "At approximately 11 p.m., Saturday Nov. 4 shots were fired within the Lone Star Rally event in the 2100 block of The Strand. There remains a very active police investigation in the area, with the street closed between 21st to 23rd Streets. "

"There are motorcycles and other property in that area that must remain in place until the investigation is complete. Police are working as quickly as possible to conduct a thorough investigation, after which owners will be allowed to claim their property.," the police said.