The haunting sound of soft singing voices can be heard as the Paris cathedral continues to be engulfed in flames in the background.

Distraught Parisians gathered to sing the liturgical song, after the fire broke out at the famed monument in central Paris on Monday.

The first reports of the blaze emerged shortly before 6pm as flames burst through the roof of the building and quickly engulfed the 315ft spire. The blaze moved through the cathedral, ravaging two-thirds of the roof and spreading to one of the two rectangular towers which formed its famous frontage.

Around 400 firefighters battled the inferno and tried to salvage artwork and other priceless pieces stored in the 12th century cathedral.

There was no immediate word on the cause of the blaze, but the structure has been undergoing a huge renovation project, including work on its spire, which can be seen collapsing into a bed of flames in anther devastating video.

Notre Dame before and after Show all 19 1 /19 Notre Dame before and after Notre Dame before and after The cathedral with the spire standing tall (left) and (right) after the fire AFP/Getty Notre Dame before and after As viewed from the Montparnasse Tower before the fire AFP/Getty Notre Dame before and after As viewed from the Montparnasse Tower after the fire AP Notre Dame before and after The heart and transept before and one day after the fire AFP/Getty Notre Dame before and after The nave of the cathedral before the fire Alamy Notre Dame before and after The nave of the cathedral after the fire Reuters Notre Dame before and after The rose window in the cathedral before the fire AFP/Getty Notre Dame before and after After the fire a hole has been exposed in the roof above the window Twitter Notre Dame before and after The cathedral from the Seine before and after Reuters Notre Dame before and after Inside the cathedral before the fire Reuters Notre Dame before and after The burning roof has left a hole in the nave Reuters Notre Dame before and after The nave after the fire was extinguished AP Notre Dame before and after Inside the cathedral after the fire Reuters Notre Dame before and after A view from the Seine of the cathedral before and after the fire Reuters Notre Dame before and after An aerial shot of Notre Dame before the fire AFP/Getty Notre Dame before and after An aerial shot of Notre Dame during the fire shows the wooden roof burning and collapsing AFP/Getty Notre Dame before and after Tourists gather near the cathedral and then seen afterwards Reuters Notre Dame before and after The spire of the cathedral is shown before and during the fire AFP/Getty Notre Dame before and after A scorched section of the exterior after the fire Reuters

To honour "Our Lady", or Notre Dame, The bells of the Church of Saint-Germain-des-Prés were heard by residents tolling its bells on Monday evening.