A medical transport plane crashed and caught fire on Tuesday on the Navajo Nation in northern Arizona, killing four people, the tribe said in a statement.

The crash involving the CSI Aviation company out of Albuquerque, New Mexico, occurred near the airport in Chinle, about 200 miles (321 kilometres) northeast of Flagstaff. Those on board were medical personnel who were on their way to a hospital to pickup a patient.

The Beechcraft 300 crashed in the early afternoon while landing at the airport, Federal Aviation Administration officials said in an email. The National Transportation Safety Board and the FAA are investigating. The tribe said the cause of the crash is unknown.