At least two people were killed and 14 others wounded when a shooting broke out early Monday in the parking lot of a Florida nightclub that was hosting a party for young teenagers.
The shooting comes just six weeks after a gunman killed 49 people at a gay club in the state the worst massacre on US soil since 9/11.
Officers have detained one "person of interest" and two other individuals for questioning over the latest shooting, which happened at Club Blu in Fort Myers.
Witnesses described people scattering when gunfire broke out shortly after midnight, ducking and running behind a nearby apartment building, with children as young as 13 reportedly among the injured.
"It was a young teen event. There were kids. The kid I was holding in my lap, he was 14 years old that got shot," Tatian Nouhaioi, a neighbor, told ABC News.
"And then there was a little girl who also got shot and she was 13. One of the security guard's daughter got shot, so I mean there was kids 13, 14, 15, 16."
Club Blu said the shooting broke out as the "Swimsuit Glow Party" was winding down and parents were picking up their children -- and despite the fact there was armed security both inside and outside the venue.
"We are deeply sorry for all involved," the club said in a statement. "We tried to give the teens WHAT WE THOUGHT WAS A SAFE PLACE TO HAVE A GOOD TIME," it added.
The Fort Myers Police Department reported that two individuals were fatally shot, "at least 14-16" more sustained minor to life-threatening wounds during the episode, which occurred at approximately 12:30 am (0430 GMT) in the club's parking lot.
A nearby home and vehicles were also shot at, resulting in one minor injury, police said in a statement.
Television images of the scene showed one of the wounded being loaded into an ambulance while police with flashlights scoured the parking lot for evidence, marking where shell casings fell.
The area has been deemed safe, but multiple streets were closed.
A police statement said "the scene is still very active as investigators and crime scene personnel attempt to determine what had occurred."
Officers are "actively canvassing the area looking for other persons who may be involved in this incident."
An attack on a gay nightclub in Orlando, Florida on June 12 left 49 dead in the worst mass shooting in US history.
Police killed the gunman, Omar Mateen, a 29-year-old US citizen of Afghan origin, after a three-hour standoff.
The Islamic State jihadist group claimed responsibility for that attack, calling Mateen "one of the soldiers of the caliphate." US authorities have said he was apparently radicalized after watching jihadist propaganda online.
That rampage and other recent shootings have revived the fraught debate about gun laws in the United States.
President Barack Obama, a Democrat, has repeatedly called for Republicans in Congress to confront the cost of their opposition to gun control and spending on mental health and drug treatment.
"We refuse to fund drug treatment and mental health programs. We flood communities with so many guns that it is easier for a teenager to buy a Glock than get his hands on a computer or even a book," he said at a recent memorial service for five police officers shot in Dallas.
After the Orlando massacre, the White House denounced the "cowardice" of US lawmakers who failed to pass gun control legislation.
Last month, Democratic lawmakers staged a virtually unprecedented 24-hour sit-in in Congress after Republicans refused to allow a vote on two widely supported measures.