A collision between a tour bus and a truck near Yellowstone National Park killed seven people and injured eight others on Thursday.
Police were alerted to the crash at 19:15 local time (02:15 GMT), when a Chevy pickup truck and a van carrying 14 tourists collided on a highway in eastern Idaho, state police said.
Both vehicles caught fire. The driver of the truck and six of the passengers in the van died.
Police are still investigating the cause. The highway where the crash took place leads into the park, which is now entering its peak tourist season.
A photo from a passerby shows smoke billowing and flames near the crumpled hood of the truck.
The witness who took the photo, local resident Roger Merrill, told the BBC’s US partner CBS News he was on his way home when he saw the scene unfolding.
Both vehicles were on fire, he said, and bystanders were trying to care for the survivors on the side of the highway.
“It is a very dangerous highway because it leads to the main entrance of Yellowstone National Park,” he said. “It’s extremely busy.”
The highway was closed for seven hours while emergency teams treated victims and cleared the crash site, about 16 miles from Yellowstone’s entrance.
Police said the local coroner’s office will release the names of the dead after family members have been notified.
Yellowstone, the US’s oldest national park, covers nearly 3,500 sq miles in three states, including Idaho, Wyoming and Montana.
It draws an average of four million tourists every year, with the majority of visitors coming between May and September, according to the National Park Service.