The famed Notre Dame Cathedral in Paris was engulfed in flames on Monday leading to the collapse of the structure's main spire. The intense flames leaped out from two of its bell towers minutes before the spire collapsed, and later spread to one of the cathedral's iconic rectangular towers.

However, the main structure of the cathedral remained intact, the Paris fire chief said, adding that the blaze was stopped from spreading to the northern belfry.

A church spokesman previously told French media that all of Notre Dame Cathedral's frame was burning after the spire collapsed. "Everything is burning, nothing will remain from the frame," spokesman Andre Finot said.

Dramatic video showed black smoke billowing from the top of the cathedral as firefighters furiously worked to contain the flames. The sight stopped pedestrians in their tracks along the Seine River, which passes under the cathedral.

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"Notre-Dame of Paris is in flames. Emotion in the whole nation. Thoughts for all Catholics and for all French," President Emmanuel Macron tweeted. "Like all our countrymen, I'm sad to see this part of us burn."

Paris emergency services said they were trying to salvage the artwork stored in the cathedral. The French capital's police department said no deaths have been reported but didn't say anything about injuries.

Paris Mayor Anne Hidalgo said that those living in the vicinity of the cathedral were evacuated from the area around 11 p.m. local time in case of a possible collapse within the structure.

In a statement, the Vatican said: "The Holy See has seen with shock and sadness the news of the terrible fire that has devastated the Cathedral of Notre Dame, symbol of Christianity in France and in the world." The fire department was fighting the flames, while the area near the cathedral was being cleared.

The Vatican said they're praying for firefighters working on the blaze, "and those who are doing everything possible to confront this dramatic situation." France's Interior Ministry said on Twitter that 400 firefighters were mobilized.

It was not immediately clear what caused the fire. Notre Dame was undergoing a $6.8 million renovation project, with some sections under scaffolding, while bronze statues were removed last week for work.

The fire started roughly five or six minutes after the cathedral closed at 6:45 p.m., France 24 reported.

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Sources told Fox News that it appears the fire, which comes one day after Palm Sunday and during Holy Week, was related to the construction done at the cathedral.

President Donald Trump tweeted about the fire, writing it was “horrible to watch the massive fire at Notre Dame Cathedral in Paris.”

U.S. Cardinal Dolan tweeted: "I just went next door to our own beloved Cathedral, Saint Patrick’s, to ask the intercession of Notre Dame, our Lady, for the Cathedral at the heart of Paris, and of civilization, now in flames! God preserve this splendid house of prayer, and protect those battling the blaze."

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Located on the Ile de la Cite in the center of Paris, the Gothic cathedral — which dates back to the 12th century — attracts millions of tourists each year. The cathedral is home to incalculable works of art and is one of the world's most famous tourist attractions.

It was featured in Victor Hugo’s novel “The Hunchback of Notre-Dame.”

The Associated Press contributed to this report.