At least four crew members of a U.S. refueling aircraft have been killed and two remain missing in Iraq. The military confirmed that the incident was not the result of hostile or friendly fire and was not caused by an Iranian armed group. The identities of the dead service members are being withheld until next of kin has been notified. This comes after seven US service members have died in the Iran war, including Army Sgt. Benjamin Pennington, who was seriously injured in an attack on U.s. troops in Saudi Arabia. The remaining two crew members are still being sought.