Three Americans were killed after their C-130 plane crashed during a firefighting mission in Australia.

The crash took place on Thursday afternoon (Australia time). Pending next-of-kin notification, the names of the three firefighters have not been released.

According to the Australian Civil Aviation Safety Authority, the mission of the C-130 was to drop fire retardant in a valley in an attempt to slow down a fire front. A C-130 modified for firefighting duties can carry approximately 15,000 liters of water or fire-retardant liquid.

“Tragically, there appear to be no survivors as a result of the crash down in the Snowy Monaro area,” said Shane Fitzsimmons, the chief of rural fire services for the southeastern state of New South Wales. “[The plane] impacted heavily with the ground and initial reports are that there was a large fireball associated with the impact of the plane as it hit the ground. There is no indication at this stage of what caused the accident.”

The aircraft had been leased by the Coulson Aviation, an aerial firefighting company from Canada. A second C-130 belonging to Coulson Aviation and operating in Australia has been grounded until the causes of the crash are identified.

Meanwhile, the Australian Transport Safety Bureau is sending an investigating team to determine the causes of the crash.

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Radar footage showing the C-130 at the moment of impact.

The Australian Federal Emergency Management Minister David Littleproud said in a statement that “The Australian Government and the Australian people feel that tragedy and that grief with them and their families, as they go through this grief and this mourning.” He added that the bodies will be repatriated as soon as possible.

Since September, catastrophic bushfires have devasted Australia. Thirty-two people have been killed. Almost one billion animals are estimated to have died by the fires. Over 2,500 homes have been destroyed. And an area of approximately the size of Louisiana has been burned to the ground. Eight firefighters, including the three Americans, have been killed in the battle against the bushfires.

The devastating bushfires.

The U.S. responded to a call for help from the Australian government by sending approximately 170 firefighters to down under.