Nigeria, March 13 -- An American refuelling aircraft has gone down over Iraq, bringing to four the number of aircraft the US has lost in the ongoing war with Iran.

At least five people were believed to be on the plane before the crash, with their fate yet to be ascertained.

The US Air Force KC-135 Stratotanker crashed in western Iraq on Thursday, the US military said. The aircraft is said to be a refuelling aircraft used to refuel fighter jets mid-air.

The US military said the crash was "not due to hostile fire or friendly fire" but involved a second US tanker, CNN reported.

At least five crew members were aboard the tanker that went down, a US official told CNN.

"A statement from US Central Command said rescue efforts were ongoing b...