Rebecca Rosman, Brian Hester and John Bacon

USA TODAY

PARIS – The structure of the Notre Dame Cathedral has been saved from a massive fire that had threatened to gut the 800-year-old beloved landmark, fire officials said late Monday.

“The worst has been avoided, although the battle is not yet totally won,” said French President Emmanuel Macron, who had rushed to the scene. Macron pledged to rebuild the church and said a national fundraising campaign would be launched Tuesday.

The blaze collapsed the cathedral’s spire and spread to one of its rectangular towers. But Paris Fire Chief Jean-Claude Gallet said the church’s main structure had been saved after firefighters prevented the flames from spreading to the northern belfry. Gallet said the emergency response had evolved into a monitoring and clean-up operation.

Paris Mayor Anne Hidalgo said in a tweet that historically significant artifacts and sacred items were saved from the fire.

"Thanks to the @PompiersParis, the police and the municipal agents," Hidalgo tweeted, "the Crown of Thorns, the Tunic of Saint Louis and several other major works are now in a safe place."

The damage to the building, however, was extensive. "Two-thirds of the roofing has been ravaged,” and firefighters would work through the night to cool down the building, Gallet said.

It was a dramatic shift from earlier in the day when officials predicted the structure would burn to the ground.

“Everything is burning. Nothing will remain from the frame,” Notre Dame spokesman Andre Finot had told French media. The 12th-century cathedral is one of the world’s most famous tourist attractions, immortalized by Victor Hugo’s 1831 novel “The Hunchback of Notre Dame.”

Throngs of spectators watched in stunned horror from nearby buildings, bridges and street. Video footage showed fire and smoke spewing from the architectural marvel, home to priceless works of art. The flames appeared to be shooting out of the roof behind the nave of the cathedral.

The fire burned for hours, virtually unabated despite the efforts of hundreds of firefighters. The flames raced on as darkness fell.

"I don’t have the words for this," said Anastasia Collas, 29, an advertising worker who watched and took video of the conflagration from the Hotel de Ville across the river from Notre Dame. "I live nearby. I want to cry. I don’t know if we’re going to lose it entirely, but this is devastating. I’m going to stay here until it ends.”

Salvage efforts had been underway to recover precious artifacts, and city prosecutors announced they were opening an investigation. Arson was ruled out as well as possible terror-related motives, officials said. Officials said the blaze could be linked to renovation work. The cathedral was in the midst of a $6.8 million renovation project.

"A special mission has been launched to try to save all works of art that can be saved," Emmanuel Grégoire, first deputy to the mayor of Paris, said on French TV.

At least one firefighter was seriously injured, officials said.

Jake Winberry, of New York, said he was heartened by strangers hugging and openly comforting each other as the blaze raged nearby, a scene that evoked memories of 9/11. "Tragedy brings people closer together," said Winberry, who is studying abroad in Paris.

Crowds huddled across the river outside the church of Saint Julien Les Pauvres to pray and sing hymns. Paris Archbishop Michel Aupetit invited priests across France to ring church bells. The blaze comes during Holy Week, an important event for the Catholic Church with Easter six days away.

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Hidalgo, the Parisian mayor, decried the "colossal damage" and said several hundred firefighters were on the scene.

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

French historian Camille Pascal told French TV the fire was destroying “invaluable heritage.”

“It’s been 800 years that the cathedral watches over Paris," Pascal said. “Happy and unfortunate events for centuries have been marked by the bells of Notre Dame.”

The renovation project was part of an effort to save the deteriorating building. Weather and pollution have taken their toll on the stone structure.

“Pollution is the biggest culprit,” Philippe Villeneuve, architect in chief of historic monuments in France, told Time magazine in 2017. “We need to replace the ruined stones. We need to replace the joints with traditional materials. This is going to be extensive.”

Construction of the cathedral took more than 100 years to complete. The result is that, although it is predominantly French Gothic, there are areas that reflect the Renaissance and the Naturalism era of construction.

Still, the cathedral is widely considered one of the finest examples of French Gothic architecture in the world. The name Notre Dame means “Our Lady” in French and is frequently used in the names of Catholic Church buildings around the world.

Rosman and Hester reported from Paris. Bacon reported from McLean, Va. Contributing: Kim Hjelmgaard in London; The Associated Press