A nine-year-old girl learning to fire an Uzi submachine gun accidentally killed her instructor at a shooting range in the United States, triggering more debate over gun control in the country.

The tragedy occurred Monday at the Last Stop roadside resort in the western state of Arizona, where the girl had been taken by her parents for a firearms lesson, the local sheriff's office said.

The little girl had successfully managed to control the military-grade weapon in the "single shot" mode at the Bullets and Burgers gun range, part of the 30-acre (12 hectares) Last Stop facility.

But when shooting instructor Charles Vacca, 39, switched the Uzi into the fully automatic setting, the force of the gunfire caused the weapon to rebound upward, and an errant bullet fired by the child struck him in the head.

"Vacca was standing next to the girl while he was instructing her how to use the weapon when the accident happened," said the Mohave County Sheriff's Office in a statement.

"Further investigations determined the girl pulled the trigger on the automatic Uzi, the recoil sent the gun over her head, and the victim was shot."

Vacca died in hospital a short time later.

Authorities later released a video, editing out the fatal shot, of the tragic shooting lesson, which had been filmed by the girl's parents.

It showed the instructor, standing on the girl's left-hand side, telling her how to place her hands and feet to shoot the weapon. She can be seen shooting one round, with only a slight recoil.

"Give me one shot... right," says the instructor, leaning in with an arm around her back.

The final frames of the video include the rapid-fire machine gun sound and the recoiling gun swinging upwards towards the instructor.

'Deeply saddening'

A manager at the firing range told NBC News that firearms training at the Last Stop can begin at as young as eight years old.

Firearms instruction at other shooting ranges in the United States, which has the world's highest per capita number of guns, can start as early as seven years old.

On its website Bullets and Burgers touts the range of automatic weapons on offer.

"Our guests have an opportunity to choose from a wide variety of machine guns," it says.

The fatal accident drew immediate reaction from gun control advocates who want tighter rules, notably on automatic weapons, and advocates of gun rights.

Mike Bazinet of the National Shooting Sports Foundation said: "Youth shooting sports are generally extremely safe activities, enjoyed by millions of Americans.

"This was a tragic and deeply saddening accident."

But Lizzie Ulmer of Moms Demand Action for Gun Sense in America said it should be a wake-up call. "We hope that this event will lead to a national discussion about children and guns," she said.

Laura Cutilletta, an attorney at the Law Center to Prevent Gun Violence, in San Francisco, said: "This tragic incident is getting a lot of coverage in the media, as it should.

"But 18 children and young people under 24 die every day in America due to our weak gun laws. We also know that in the US over 1.69 million kids age 18 and under are living in households with loaded and unlocked firearms.

"That needs to change."