A fire has broken out at the famous Notre-Dame cathedral in Paris and has spread rapidly across the building.
The cause was not immediately clear, but officials say that it could be linked to renovation work.
Images on social media show plumes of smoke billowing into the air above the 850-year-old Gothic building.
Last year, the Catholic Church in France launched an urgent appeal for funds to save the cathedral, which was starting to crumble.
A major operation is under way to tackle the blaze, which broke out on Monday afternoon. An area surrounding the building in central Paris has been cleared, officials said.
French President Emmanuel Macron has cancelled his planned speech to the nation in light of the fire, which has engulfed the giant spire of the cathedral, an Élysée Palace official said.
The mayor of Paris, Anne Hidalgo, described it as a “terrible fire” and urged people at the scene to respect the boundaries set up by fire crews in order to ensure that they remain safe.
US President Donald Trump suggested “perhaps flying water tankers” could be used to extinguish the fire.
The Notre-Dame cathedral, which is visited by millions of people every year, is undergoing renovations after cracks began to appear in the stone, sparking fears the structure could become unstable.