French prime minister announces competition to rebuild Notre Dame Cathedral's iconic spire

Flames engulfed the world-famous medieval Catholic cathedral on Monday evening.

LONDON -- France's prime minister has announced "an international architecture competition" to rebuild the iconic arrow-like spire atop the Notre Dame Cathedral in Paris, which caught fire on Monday evening.

The 300-foot spire toppled over in flames on Monday night as a massive fire engulfed the world-famous medieval Catholic cathedral, an 850-year-old landmark situated in the middle of the Seine river on a tiny island within the French capital. Firefighters battled the blaze for nine hours before quelling the flames.

No one was killed in the fire, the cause of which is under investigation.

The cathedral was partially encased in scaffolding while undergoing a $170 million renovation at the time of the blaze. Much of the ribbed oak roof, made up of centuries-old wooden beams, was destroyed.

Yet, despite the extensive damage, which will take years to repair, the facade of the historic edifice appears to be mainly intact with its belfries and many other iconic features spared.

Msgr. Patrick Chauvet, who was at the cathedral when the flames erupted during a mass, told reporters the famous 18th-century organ, which boasts 8,000 pipes, and three rose-stained glass windows, which date back to 1250, both survived the inferno.

A bronze rooster that sat atop a cross on the spire was also found only slightly damaged, according to Chauvet.

Valerie Pecresse, president of the Ile-de-France region that encompasses Paris, called it a "miracle" that the walls of the Gothic cathedral are still standing.

Firefighters remained on site Wednesday working to secure the structure, dampening potential hotspots and removing priceless artwork, artifacts and relics, according to a spokesperson for the Paris Fire Brigade.

French President Emmanuel Macron said in a televised address Tuesday that he wants to see the fire-gutted cathedral restored in five years and it will be "even more beautiful." Nearly $1 billion in donations from worshipers and billionaires around the world has already been pledged to help rebuild it.

The blaze came at the start of Holy Week, the busiest and most important period of the liturgical year. Easter is on Sunday.

Bells at all of the churches and cathedrals across France will ring out in unison on Wednesday evening in honor of the Notre Dame Cathedral.

ABC News' Clark Bentson, Ben Gittleson, Angus Hines, Bill Hutchinson, Julia Jacobo, Mikey Kay, James Longman and Phoebe Natanson contributed to this report.