A suggestion by President Donald Trump on how to fight the fire that devastated the Notre Dame cathedral in Paris Monday could have caused the entire building to collapse, France's crisis management agency said.

As the flames raged, Trump tweeted, "So horrible to watch the massive fire at Notre Dame Cathedral in Paris. Perhaps flying water tankers could be used to put it out. Must act quickly!"

The French General Directorate for Civil Security and Crisis Management said on Twitter that using aircraft was the one thing they shouldn't do.

"Hundreds of firemen of the Paris Fire Brigade are doing everything they can to bring the terrible #NotreDame fire under control. All means are being used, except for water-bombing aircrafts which, if used, could lead to the collapse of the entire structure of the cathedral," the agency tweeted.

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In a separate tweet, the agency clarified by adding "the weight of the water and the intensity of the drop at low altitude could indeed weaken the structure" and that there could be collateral damage to nearby buildings. It also said the same would be true whether the water was dropped by helicopter or airplane.

Much of the building was destroyed, but Paris fire commander Jean-Claude Gallet said a major accomplishment of hundreds of firefighters was stopping the flames from spreading to the north tower belfry.

Gallet said two-thirds of Notre Dame's roofing "has been ravaged." He says one firefighter was injured.

France Notre Dame Fire
A firefighter tackles the blaze as flames and smoke rise from Notre Dame cathedral as it burns in Paris, Monday, April 15, 2019. (AP Photo/Michel Euler)
AP