Emirates 24/7 — A U.S. Air Force KC-135 Stratotanker, a refueling aircraft, crashed in western Iraq on Thursday during a mission involving a second tanker, U.S. Central Command (CENTCOM) confirmed. The military stated the incident, which occurred during “Operation Epic Fury”—the Pentagon’s designation for operations against Iran—was “not due to hostile fire or friendly fire.”

At least five crew members were aboard the aircraft when it went down in a sparsely populated desert area. While CENTCOM confirmed that the second aircraft involved landed safely, rescue efforts for the downed tanker remain ongoing. A U.S. official said that details regarding casualties are still being gathered, as the military seeks to provide clarity for the families of the service members involved.

The KC-135 serves as a vital “flying gas station,” allowing jets to refuel mid-air to extend their range and remain within a battle zone for longer. This crash marks the fourth known aircraft loss in the current conflict with Iran, following last week’s friendly fire incident in which three F-15E Strike Eagles were downed over Kuwait.