Four people were killed Tuesday when a medical transport plane crashed on Navajo Nation land in Arizona, USA.

Axar.az informs, citing CNN, “The small aircraft was enroute to pick up a patient from a nearby hospital, when the crash occurred,” Navajo Nation Police said on Facebook.

The accident took place near Chinle, Arizona, according to police.

“We extend our deepest condolences to their family and loved ones during this time,” Navajo Police said.

The plane was a Beechcraft 300, the National Transportation Safety Board said.

“NTSB investigators are en route to the scene (and) expected to start arriving tonight. Once on site, the investigators will begin the process of documenting the scene and examining the aircraft. The aircraft will then be recovered to a secure facility for further evaluation,” Sarah Taylor Sulick, a spokesperson for the NTSB, told CNN.