An American military aerial refueling tanker that was involved in the U.S. military operation in Iran crashed in western Iraq on Thursday, multiple U.S. officials told CBS News.

All ⁠six ⁠crew members aboard a U.S. ⁠military KC-135 refueling aircraft that crashed in western Iraq are confirmed to ​have been killed, the U.S. military said on Friday.

"The circumstances of the incident are under investigation. However, the loss of the aircraft was not due to hostile fire or friendly fire," read a statement from U.S. Central Command Friday morning.