A 13-year-old boy was killed and his twin brother severely injured in a motor-home crash in Yellowstone National Park Tuesday.

At roughly 5:30 p.m., a rental RV was involved in a single-vehicle accident on the South Entrance Road in the vicinity of Lewis Falls, Linda Veress with Yellowstone Public Affairs said.

The boy, who died at the scene was identified as Nathaniel Robert Ullom of Elizabeth, Colorado. His twin brother, Phillip Ullom III, was flown to an Idaho hospital with serious injuries.

Their father, Phillip Ullom, was taken by ambulance to a hospital in Jackson.

Veress added that the road leading to the park's south entrance was closed for a few hours.

The accident is still under investigation.

No further details have been released.