Notre-Dame has been saved from total destruction after a blaze ripped through the cathedral, French fire services have said.
Flames broke out at the 12th century historic building on Monday evening, quickly devastating the spire and roof and sending plumes of black smoke into the sky.
French President Emmanuel Macron said he was “so sad tonight to see this part of all of us burn” and declared a national emergency.
Speaking from the scene in Paris, he expressed sympathy with Catholics “around the world” following the “terrible tragedy” but added the worst had been avoided.
He vowed to launch an international fundraising campaign for the cathedral so the world could rebuild Notre-Dame together.
France’s interior minister originally warned the 400 firefighters scrambled may not be able to save the cathedral.
But a junior minister from the department later said they were more optimistic the cathedral could be spared, with up to four more hours needed to contain the blaze.
A French firefighter official confirmed Notre-Dame’s structure and two towers had been saved from total destruction.
Prime Minister Theresa May said her “thoughts are with the people of France tonight and with the emergency services who are fighting the terrible blaze”.
Video filmed by witnesses showed the moment the historic landmark’s steeple was consumed by flames before toppling over.
Hours later the area where the spire had once been was still burning with sparks falling from the cathedral’s vaulted ceiling.
One described people “howling and gasping” as they watched the destruction unfold.
Another witness said they saw a fire breaking out in one of the cathedral’s towers.
“Everything is burning, nothing will remain from the frame,” a Notre-Dame spokesman told local media.
Paris mayor Anne Hidalgo urged the public to “respect the security perimeter” around the cathedral while firefighters tackled the “terrible” blaze, and added that the areas close to the scene were evacuated.
The city’s deputy mayor also said Notre-Dame had suffered “colossal damages” and emergency services were trying to salvage the art and other priceless pieces stored inside it.
A firefighter at the scene confirmed all efforts were being put into saving artwork at the back of the cathedral and stopping the northern tower from collapsing.
Its priceless treasures include the crown of thorns – a Catholic relic which is only occasionally displayed.
Paris prosecutors have opened an investigation into the fire. They have ruled out arson and possible terror-related motives and instead think the blaze was started by accident.
British Foreign Secretary Jeremy Hunt said he was thinking of his French counterpart.
“Heartbreaking for the millions who love this great cathedral and great city across the world. Wishing you all the best in tackling the blaze and its consequences,” he wrote on Twitter.
UNESCO’s director Audrey Azoulay said there was “huge emotion” and the organisation “stands alongside France to help safeguard and rebuild this inestimable piece of our heritage”.
Former US president Barack Obama also wrote on Twitter: “Notre Dame is one of the world’s great treasures, and we’re thinking of the people of France in your time of grief. It’s in our nature to mourn when we see history lost – but it’s also in our nature to rebuild for tomorrow, as strong as we can.”
The Vatican, the head of the Catholic Church, said it was praying for French firefighters.
And the Archbishop of Paris called on all priests in the city to ring their church’s bells as a gesture to Notre-Dame.
The cathedral dates back over 800 years and is famous for featuring in Victor Hugo’s classic novel the Hunchback of Notre-Dame.
It was in the midst of renovations, with some sections under scaffolding, while bronze statues were removed last week for works.
The attraction is visited by millions of tourists every year and translates in English as “Our Lady”.
Its first stone was laid in 1163 in the reign of Louis VII, as the medieval city of Paris was growing in population and importance, becoming the political and economic centre of the kingdom of France.
Construction continued for much of the next century, with major restoration and additions made in the 17th and 18th
The 387 steps up to the towers take visitors past the gallery of chimeras, mythical creatures typically composed of more than one animal.