It was reported today by the Australian Defense Force that two U.S. jets "emergency jettisoned" two bombs each on Australia's Great Barrier Reef after a failed training exercise on Tuesday.

The two jets, AV-8B Harriers, were originally scheduled to bomb a bombing range on a nearby island with one inert bomb and one explosive bomb each during a training run, but after several failed attempts to do so, the aircraft were forced to return to their starting point but could not land loaded.

The U.S. 7th Fleet said that the two aircraft dropped their ordinance in a deep channel near the reef to minimize damage to the reef. Officials from both the U.S. and Australia have issued navigational notices to warn vessels transiting the area until navigational charts can be updated showing the position of the unexploded ordinance.

The Austrailian Defense Force stated that the bombs “pose minimal risk to the public or the marine environment.”

The incident occurred on the second day of the Biennial joint training execise. The three-week execise is attended by 28,000 Austrailian and American personnel.

The incident involving the aircraft from the 31st Marine Expeditionary Unit is currently under investigation.