The US military has named all six crew members who were killed when their refuelling aircraft crashed in Iraq.

The Pentagon said the airmen on board the KC-135 plane were: John Klinner, 33, from Alabama; Ariana Savino, 31, from Washington; Ashley Pruitt, 34, from Kentucky; Seth Koval, 38, from Indiana; Curtis Angst, 30, from Ohio; and Tyler Simmons, 28, also from Ohio.

The first three were Air Force personnel, and the latter three served in the National Guard.

The US military previously said neither hostile nor friendly fire were involved in the loss of the plane in western Iraq on Thursday.

The aircraft was on a combat mission as part of ongoing US operations against Iran and was one of two planes involved in the incident. The second landed safely.

US Defense Secretary Pete Hegseth hailed the aircraft's crew members as "American heroes".

US officials told CBS News, the BBC's US partner, the incident may have involved a midair collision, but added that they were still investigating.

Centcom earlier described the crash as happening over friendly airspace.

An Iraqi intelligence source told CBS the first plane went down near Turaibil, located on the Iraqi-Jordanian border.

Pro-Iranian militias operate in western Iraq. Iran's military claimed on state TV that an allied group had targeted the plane with a missile.

Thursday's crash brings the official US military death toll in the US-Israel war with Iran, which began a fortnight ago, to 13. Six more soldiers were killed in Kuwait and one other in Saudi Arabia.

To date, the US military has lost at least four aircraft during the war, which started with US and Israeli strikes on Iran on 28 February.

Boeing manufactured the KC-135 Stratotanker for the US military in the 1950s and early 1960s.

It has been a backbone to the US military's air refuelling fleet, and allows combat aircraft to carry out longer missions without needing to land.