Four out of six crew members were killed after a US refuelling aircraft crashed in western Iraq on Friday, US Central Command confirmed.According to the US military, the circumstances of the incident are under investigation. However, it rejected that the crash was a result of hostile fire or friendly fire.

BIG! American KC-135 Refueling Plane Crashes Over Iraq; Five Member Crew Missing | IRAN WAR

“At approximately 2 pm ET on March 12, a US KC-135 refueling aircraft went down in western Iraq. Four of six crew members on board the aircraft have been confirmed deceased as rescue efforts continue,” US military Central Command said.“The circumstances of the incident are under investigation. However, the loss of the aircraft was not due to hostile fire or friendly fire. The identities of the service members are being withheld until 24 hours after next of kin have been notified,” it added.The KC-135 tanker marks at least the fourth US military aircraft lost in the Middle East conflict, after three F-15E fighter jets were earlier shot down in a friendly-fire incident over Kuwait.The KC-135, a refuelling aircraft that has been in service for more than six decades, typically operates with a three-person crew, a pilot, a co-pilot and a boom operator responsible for refuelling other aircraft, according to the US Air Force.Some missions also require a navigator, and the aircraft is capable of carrying up to 37 passengers, an Air Force factsheet says.Earlier in the conflict, which began on February 28, Kuwaiti forces mistakenly shot down three American F-15E fighter jets, though all six crew members ejected safely, according to US Central Command. The incident took place amid active combat involving attacks by Iranian aircraft, ballistic missiles and drones, the command said at the time.