A small plane carrying four passengers crashed in mountainous terrain in northern Wyoming, killing a 13-year-old girl and injuring three relatives, authorities said.

On Monday at approximately 4:57 p.m. the Sheridan Law Enforcement Center in Wyoming received initial reports of possible lost or injured people in the area of Big Mountain within the Bighorn National Forest.

“Additional reports came in that an aircraft had possibly crashed in the area of Big Mountain within the Bighorn National Forest,” according to a press release from the Sheridan County Sheriff’s Office. “Sheridan County Sheriff’s Deputies, Sheridan Area Search and Rescue (SASAR), and Wyoming Regional EMS (WREMS) responded to the area.”

Authorities flew a small plane over the area and confirmed there was evidence of a plane crash west of Big Mountain, authorities said.

Rescue and medical teams were dispatched to the crash site and found a single engine aircraft with three surviving passengers and a 13-year-old girl who was confirmed deceased on scene.

“The three patients, an 11-year-old male, a 54-year-old male and a 53-year-old female, all of the same family, were reported to have serious injuries,” according to the sheriff’s office. “Medical and rescue teams worked to stabilize the three patients. A Wyoming Army National Guard helicopter was requested to respond for hoist operations.”

The three surviving passengers were taken to two separate hospitals where their conditions are currently unknown. The deceased girl’s body was transferred to the Sheridan County Coroner and officials said that she will be publicly identified at a later time.

“The coordinated effort between all of the rescuers, EMS, medical teams, and aircraft personnel was exceptional,” Sheridan County Sheriff Levi Dominguez said. “This was, and still is, a very fluid scene. Our thoughts and prayers are with the victims’ and their family.”

Local authorities said that officials from the Federal Aviation Administration were making their way to the site of the crash to conduct an investigation.

The sheriff’s office has asked the public to stay out of the area and that the investigation into the incident is currently ongoing.