The US military on Friday announced that the entire crew of six was killed when an aerial refuelling aircraft crashed in Iraq – an incident it said was not caused by "hostile fire".

"All six crew members aboard a US KC-135 refueling aircraft that went down in western Iraq are now confirmed deceased," US Central Command said in a social media post.

"The circumstances of the incident are under investigation. However, the loss of the aircraft was not due to hostile fire or friendly fire," said the military command, which is responsible for US forces in the Middle East.

This brings the total of confirmed US deaths in the operation against Iran to 13.

Iran's military said in an earlier statement carried by state TV that an allied group in Iraq had downed the aircraft with a missile, killing all its crew.

The Islamic Resistance in Iraq, which is a loose alliance of Iran-backed Iraqi factions, claimed to have downed a KC-135. They also said they had targeted another plane that escaped.

Since the start of the Middle East war, the alliance has been claiming daily attacks on US interests in Iraq and across the region, but it rarely names its targets.

The KC-135 is at least the fourth US military aircraft lost during the war, after three F-15s were shot down by friendly fire over Kuwait. (AFP)


Edited by Aaron Tam