A fire has broken out at the famous Notre-Dame cathedral in Paris and has spread rapidly across the building., the BBC reports.
The cause was not immediately clear, but officials say that it could be linked to renovation work.
Last year, the Catholic Church in France launched an urgent appeal for funds to save the cathedral, which was starting to crumble.
The peak of the church is undergoing a €6 million ($6.8 million) renovation project and French media have quoted the Paris fire brigade as saying the fire is "potentially linked" to the renovation work.
A major operation is under way to tackle the blaze. An area surrounding the building in central Paris has been cleared, officials said.
The French president has reacted in a tweet: "Notre-Dame de Paris is engulfed in flames. Emotion of a whole nation. Our thoughts go to all Catholics and all French people. Like all our compatriots, I am sad this evening to see this part of us burning."
Notre-Dame de Paris en proie aux flammes. Émotion de toute une nation. Pensée pour tous les catholiques et pour tous les Français. Comme tous nos compatriotes, je suis triste ce soir de voir brûler cette part de nous.— Emmanuel Macron (@EmmanuelMacron) April 15, 2019
The French capital's police department said no deaths have been reported, though it didn't say anything about injuries, France 24 said.
A Notre-Dame spokesman, Andre Finot, said the cathedral's wooden interior is likely to be completely destroyed by the fire.
"Everything is burning, nothing will remain from the frame," he told French media.
Built in the 12th and 13th centuries, the church receives almost 13m visitors each year, more than the Eiffel Tower.