The boy and hang-gliding instructor were killed after the truck towing their glider took a sharp turn. Wikimedia Commons

A 12-year-old boy and his instructor have been killed after their hang glider crashed in the US state of Nevada on Friday (27 March).

Police said the pair were being towed by a truck, which took a sudden sharp turn as the driver mistakenly believed they had detached themselves from the vehicle.

"The glider was supposed to release the tether from the truck itself," said Captain Peter Boffelli from the Las Vegas Metropolitan Police Department. "Apparently, that tether release did not occur. So what occurred is when the truck turned around thinking the tether was released, the glider itself plummeted straight to the ground."

The accident occurred at a dry lake bed near Jean, which is about 30 miles (48km) south of Las Vegas.

The adult male instructor was pronounced dead at the scene of the crash, the Las Vegas Sun reported.

According to the paper, the hang gliding team put the boy in the back of a pickup truck to transport him to hospital in Las Vegas.

They pulled over next to a Nevada Highway Patrol trooper who performed CPR but was unable to revive him.

Medical personnel who arrived on the scene pronounced him dead.

Authorities did not provide details of the name or age of the hang-gliding instructor. The child has not been named.

Boffelli told reporters it was too early to determine whether the accident was due to a mechanical or operational issue.

The incident is being investigated by the police and the Federal Aviation Administration.