A United States refueling aircraft crashed in western Iraq on Thursday, killing four of the six crew members on board, according to a statement from the US Central Command (CENTCOM) released on Friday. The remaining two crew members are still being sought as rescue operations continue in the area.

CENTCOM said the KC-135 refueling aircraft went down in friendly airspace during Operation Epic Fury. The command confirmed that two aircraft were involved in the incident, with one crashing in western Iraq while the other landed safely. CENTCOM emphasized that the crash was not caused by hostile action or friendly fire.

The incident adds to ongoing operational challenges for US forces in the region, though CENTCOM has not released further details about the cause of the crash or the status of the rescue efforts.