Three people were killed and 15 others injured in a mass shooting between two rival groups at an unsanctioned car show on Friday in the US state of New Mexico, according to local authorities.

The shooting took place at Young Park in the city of Las Cruces, about 22:00 local time.

“There have not been arrests or anyone detained” but the department was seeking leads, Las Cruces police chief Jeremy Story said at a Saturday press conference.

Two 19-year-old men and one 16-year-old boy died in the shooting, police said.

“There was an altercation between two groups of people and that altercation escalated to gunfire between both groups,” Mr Story said. “Several other people were also injured in the crossfire.”

Mr Story said there had been “ill will” between the two groups prior to the car show.

About 50-60 bullet shell casings from handguns were found at the scene, police said, adding that the crime scene was huge and about 200 people had been at the park.

Police have asked any witnesses to come forward with information or video.

Those injured in the shooting ranged from ages 16 to 36. Authorities have not yet named any of the victims.

Seven patients were sent to nearby El Paso, Texas, which is just over the New Mexico border, for further medical treatment, said fire chief Michael Daniels.

Four other victims had been treated and released, Mr Daniels said.

“Today we mourn a tragic, a senseless, a horrible event that happened in our city last night,” said Las Cruces Mayor Eric Enriquez.

“There’s no place for violence like this in our community, and we will continue to work tirelessly to make our community safe,” he said.

Police responded to reports of gunfire and potential gunshot victims near the parking lot about 22:00 local time.

Bystanders had already started administering treatment, Story said, and fire department officials began to treat victims before the scene was fully secured.

Local emergency officials, as well as individuals from the Federal Bureau of Investigation and federal Bureau of Alcohol, Tobacco, Firearms and Explosives, responded to the shooting, Enriquez said.

The New York Times reported that the event was a monthly gathering for modified sports car enthusiasts.

Mr Story told the press that the car shows had become “an issue.”

The police chief said that firearms had been present at the car gathering. He said that some were “used the shooting,” but that other people at the park that night were carrying firearms “willy nilly” that were not involved in the incident.

The US has a long-running political debate over the degree to which citizens should be permitted to purchase and carry guns.

Though the US Constitution guarantees Americans the right to “keep and bear arms”, federal law broadly governs gun access, each of the 50 states have different regulations about buying, owning, and carrying firearms.

The state of New Mexico allows people to openly carry guns in public without a permit.

It does however require a permit to carry a concealed firearm in public, and residents can apply for a permit through the state if they meet certain requirements.

Authorities did not provide details about the legal status of the guns used in Friday’s shootings.

Mr Story said that the shooting was “senseless” and served as a reminder of the need for the “rule of law” in New Mexico.

But he added that “this news conference will not be political” because “now is not the time”.