French president Emmanuel Macron says watching Notre Dame cathedral go up in smoke was like watching "a part of us burn".
The famous medieval church Notre Dame cathedral fire: Dramatic video shows famous Paris church roof engulfed by flame , with flames soon engulfing its iconic spire and threatening the entire wooden frame of the building. The roof of the church, as well as the 300ft spire, collapsed completely as smoke filled the Paris skyline.
The president, who cancelled a planned speech in light of the emergency, wrote on Twitter: "Notre-Dame de Paris in flames. Emotion of a whole nation. Thoughts for all Catholics, and all of the French.
"Like all our countrymen, I am sad this evening to see this part of us burn."
Sharing video of the damage on Twitter, author Shiv Malik said: "The central spire collapse into the heart of the building and now the twin bell towers are being torched by the ferocity of the flames."
According to French media, the fire may be linked to the renovation work which had been ongoing at Paris' most-visited landmark.
A church spokesman said all of the Where is Notre Dame? Iconic Paris cathedral on fire in France on Monday 's frame was burning after the spire collapsed, while the emergency services fought to salvage the priceless artwork stored in the cathedral.
Paris mayor Anne Hidalgo described it as a "terrible fire" and urged people at the scene to stay safe.
Smoke also began to fill the church's famous bell towers - the setting for much of Victor Hugo's The Hunchback of Notre-Dame - and it's unclear as yet how much more of the 850-year-old church, which survived desecration during the French revolution, will be salvagable.
It's not know whether anyone has been hurt.
Where is Notre Dame? Iconic Paris cathedral on fire in France on Monday
Notre Dame cathedral fire: Dramatic video shows famous Paris church roof engulfed by flame
