US President Donald Trump said water should be dropped on the 850-year-old church in Paris. He wrote on Twitter: “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!”
But the French authorities were unable to use this tactic in fear of it injuring people nearby as well as destroying the iconic monument.
A water bomber jet can tame intense fires by dropping up to six tonnes of water.
The jet called Canadair drops the water at high speed.
French news site Le Monde said: “A Canadair projects about six tonnes of water at high speed to the ground.
READ MORE: Notre Dame fire: Horror as Paris cathedral spire COLLAPSES
“The danger is significant of hurting one or more people around the building – which is why Canadair interventions are so infrequent in urban and peri-urban areas.
“Such an intervention could also significantly destroy the little remaining structure of the cathedral.”
French President Emmanuel Macron has vowed to rebuild the cathedral.
He said: “Notre-Dame is our history, our literature, part of our psyche, the place of all our great events, our epidemics, our wars, our liberations, the epicentre of our lives.
“Notre-Dame is burning, and I know the sadness, and this tremor felt by so many fellow French people.
“But tonight, I’d like to speak of hope too,” he said, announcing the launch of a fundraising campaign.
“Let’s be proud, because we built this cathedral more than 800 years ago, we’ve built it and, throughout the centuries, let it grow and improved it.
“So I solemnly say tonight: we will rebuild it together.”