A huge fire that caused extensive damage Monday to Paris’ Notre Dame, the world-famous, 850-year-old cathedral, has been extinguished.

“There is no indication that this was a deliberate act,” Paris prosecutor Rémi Heitz told a press conference Tuesday morning, adding that investigators considered an accident the most likely cause.

Heitz said interviews have begun with around 15 workers from the five companies that were working at the site as part of a renovation project. The Paris police have mobilized around 50 investigators, he added.

According to the Associated Press (AP), assessments are being made to see if it is safe to enter the blackened structure, after the cathedral’s roof and spire collapsed Monday evening. Two police men and a firefighter have been reported injured.

The French Interior Ministry said earlier on Twitter that over 400 firefighters had been mobilized to battle the blaze. They managed to save much of the landmark’s structure – including its two iconic 226 ft bell towers. The cathedral’s 18th-Century organ, one of the world’s most famous musical instruments, is intact, according to the AP. Much of the artwork in the building has also been recovered.

“Generally the structure is holding up [but] we have identified some vulnerabilities, particularly around the arched roof and one gable in the north transept,” said French Interior Ministry official Laurent Nuñez on Tuesday.

French President Emmanuel Macron tweeted that the burning cathedral was the “emotion of a whole nation.”

“Like all our countrymen, I am sad tonight to see this part of us burn,” he tweeted as news of the fire began to spread.

In a speech later Monday night, in the vicinity of the still-burning cathedral, Macron pledged to rebuild Notre Dame.

“I’m telling you right now, very solemnly, we will rebuild this cathedral all together,” he said, vowing to seek out help at home and abroad. “I’m committed to this project.”

The Vatican released a statement on Monday evening conveying Pope Francis’ “shock and sadness” at the destruction of a worldwide “symbol of Christianity.”

“We express our closeness to the French Catholics and the population of Paris and assure you of our prayers for the firefighters and how many are doing their best to cope with this tragic situation,” the statement read.

Earlier Monday, President Donald Trump tweeted that it was “horrible to watch” Notre Dame burning and suggested that French authorities use “flying water tankers” to extinguish the flames.

France’s civil security agency said that it had used “all means” to put out the fire, except for water-dropping aircraft, like the U.S. President suggested. They said that dropping that amount of water on the 12th century structure could cause the entire building to fall.

Videos and images of the enormous fire engulfing the medieval Catholic cathedral flooded social media throughout Monday. In them, enormous plumes of smoke were seen erupting from the cathedral, with flames leaping up to its bell towers and spire before it collapsed.

Here are a few of the many Twitter posts that show the fire.

Many Twitter users documented the moment that the cathedral’s spire, which was reconstructed in the 19th century, fell.

Construction of Notre Dame began in 1163, according to the cathedral’s website, and was completed in about 1250. It is one of Europe’s most-popular tourist attractions, drawing about 12 million people a year to its doors. The cathedral was also celebrated in Victor Hugo’s classic novel The Hunchback of Notre Dame, which was published in 1831.

Its great age caused the cathedral to fall into a state of disrepair in recent years, with no clear decision about who would take up the cost for expensive restorations.

Because of the fire, Macron canceled a planned address to the nation, which was expected to cover ongoing civil unrest.

Additional reporting by John Walcott

This story is developing…

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