It’s pretty damn near impossible to have a friendly fire incident of this magnitude when you are not actively engaged in battle with an actual enemy.
It IS impossible. I think it may be a set up or a trap.
The Iranian government isn't going to tell US the truth. I bet the King of the K.S.A. knew about it ahead of time.
Our forces ARE still there in north and west of the K.S.A. at the mouth of the Tigris and Euphrates Rivers. It's more mud than delta.
There USED to be the wetlands of Iraq, once inhabited by the Marsh Arabs. The area was almost completely dried out, and have only recently shown signs of recovery. The Tigris–Euphrates Basin is shared by Turkey, Syria, Iraq, Iran and Kuwait.