The overnight confirmation that a US KC-135 went down over Western Iraq marks the single deadliest aerial incident suffered by the United States since the start of Operation Epic Fury. A Friday morning Pentagon briefing has confirmed that four of the six crew members on board have died, as rescue efforts for the two other service members continue.
"The circumstances of the incident are under investigation," it said in a statement on Friday. The Pentagon and US CENTCOM have sought to emphasize the KC-135 aircraft was not downed "due to hostile fire or friendly fire," adding that it had crashed at about 2pm Eastern Time (19:00 GMT).

CENTCOM further said it had occurred in "friendly airspace" (of Iraq) but was operating in connection with Operation Epic Fury against Iran.
Adding to the confusion in terms of precisely what happened, the incident appeared to involve two planes, possibly colliding or engaging in close maneuvers, with the second plane - possibly damaged - having "landed safely" in Israel.
The initial official statement CENTCOM issued Thursday evening said:
U.S. Central Command is aware of the loss of a U.S. KC-135 refueling aircraft. The incident occurred in friendly airspace during Operation Epic Fury, and rescue efforts are ongoing. Two aircraft were involved in the incident. One of the aircraft went down in western Iraq, and the second landed safely.
The identities of the service members were being withheld, pending notification of their families.
Pro-Tehran forces have contradicted the whole narrative, claiming instead that they shot the Air Force refueling jet down.
Already Iraqi Shia militia groups have been attacking US bases in Iraq, and are now claiming responsibility for the refueling tanker attack, per CBS:
A group of Iranian-backed militias that collectively refer to themselves as the Islamic Resistance in Iraq claimed Friday that they had caused the deadly crash of an American KC-135 refueling tanker plane in western Iraq, and hit a second aircraft of the same kind.
The Islamic Resistance in Iraq, in a second claim issued online Friday, said it had "targeted, with appropriate weapons, a second KC-135 aircraft belonging to the American occupation in western Iraq during the past twenty-four hours. Its crew managed to escape after it was hit, and it made an emergency landing at one of the enemy's airports."
There's already been a build-up of skepticism over the 'accident' claims surrounding a growing list of curious battlefield episodes among many pundits.
Still, there's plenty of speculation of what could have caused such a major aerial accident - if it proves such:
Al Jazeera’s Rosiland Jordan, reporting from Washington, DC, said the information shared by CENTCOM is still vague on exactly what happened, despite announcing that the aircraft was not shot down by allies or enemies.
"It looks as if this may have been a refueling attempt or operation, and then this air tanker went down," she said.
Before the aircraft crash, the US military had reported that seven service members had died in the ongoing military campaign, and an eighth died in Kuwait from a “health-related incident” during a medical emergency.
War Secretary Pete Hegseth said in a Friday morning Pentagon press briefing while confirming the deadly refueling tanker incident that "bad things can happen."
The second apparently damaged tanker made an emergency landing in Israel. Purported photos at Ben Gurion Airport of the aircraft:
"War is hell," he said. "War is chaos." He further hailed the plane's crew as heroes and said that "their sacrifice will only recommit us to the resolve of this mission." He added: "But war in this context and in pursuit of peace is necessary."