All three people reported onboard a cargo plane that crashed in Alaska's Denali National Park on Sunday were believed to have died in the incident, a park official said.
Authorities were checking the identities of those thought to be onboard, and working toward identifying next of kin, park spokeswoman Kris Fister told msnbc.com.
The plane ignited into a fireball and sparked a blaze at the park, which complicated efforts on the scene, she said.
"We haven't been able to thoroughly examine the wreckage because of the fire," Fister said, although the blaze had been brought under control.
Firefighters were mainly dousing the area in an attempt to preserve the scene for investigators from the National Transportation Safety Board, due to arrive at the crash site Monday morning. Park rangers were securing the scene overnight, Fister added.
The Fairchild C-123, went down near the park's eastern edge at 3:15 p.m. (9:15 a.m. ET), about 100 yards off the only major road in the park. The aircraft was registered to All West Freight, Inc. of Delta Junction, Alaska, Fister said.
'Big ball of flame'
Anchorage resident Jeff Kowalczyk, who witnessed the crash, said the crash site was "a big ball of flame," NBC affiliate KTUU-TV reported.
"We looked back and it started banking to the pilot's left, kept banking more and more until it was upside-down and crashed in the hill right in back of us," Kowalczyk said.
"We walked around the perimeter, took about a half-hour for the park rangers to show up and help out — but we saw one body, one body burned pretty bad, pilot probably," he added.
George Clare, of Las Vegas, told The Associated Press that he saw the plane flying very low and slowly while he was walking toward the visitor's center near the park entrance. He thought the plane was going to land on a local airstrip, so he proceeded to the visitor's center. Within minutes, people came running in and saying a plane had crashed.
The crash caused a column of smoke a few miles west of the visitor's center, he said.
Clare said the aircraft looked like a military plane.
"It was a military khaki green kind of color," he said. "It was propeller-driven. It was a fixed wing aircraft and it had kind of a flat underbelly."
Doug Stockdale with the Alaska Fire Service said the fire was initially estimated at two acres but could have grown larger. Smokejumper fire crews were flown to the scene, he said.
The crash happened just four days after a military cargo plane crashed at Elmendorf Air Force Base in Anchorage, killing four people onboard.
The four airmen were on a training mission Wednesday evening for a weekend air show at the Air Force base, which wrapped up Sunday. The C-17 crashed about a minute after taking off.