French President Emmanuel Macron vowed Tuesday to rebuild the fire-ravaged Notre Dame Cathedral in Paris within five years, saying an "even more beautiful" landmark is possible.

The iconic house of worship was almost destroyed by flames Monday, and Macron said in a nationally televised address that France would spare no money or effort to make it whole again.

"And I tell you tonight with force, we are this people of builders," Macron said, according to a translation by NBC News.

"We have so much to reconstruct. So yes, we will rebuild the Cathedral of Notre Dame more beautifully. And I would like it to be achieved in five years from now. We can do it. And we will mobilize."

Macron set a five-year target of completion and asked the nation to think deeply about "what we are and what we are to become, to become better than we are today."

He urged the public to unite and turn the national "catastrophe" into a moment of French unity. He said the reconstruction of Notre Dame Cathedral will be a "passionately French" project.

"I believe profoundly that we will turn this tragedy into a moment to come together, to be reflective of what we were and what we have to be. We must be better than we were," Macron said.

"It will come back. To find the threads of our national project, that which made us, which unites us, a human project, passionately French."

Macron reminded the nation that all structures, even one as grand as Notre Dame Cathedral, are subject to destruction by human error — and just as easily can be fixed by people working together.

"Throughout our history, we built cities, ports, churches. Many burned, were destroyed by wars, the fault of men," he said.

"Every time, every time, we have rebuilt them. The fire of Notre Dame reminds us that our history will never end. Never. And that we will always have challenges to overcome."

Macron added: "That which we thought was indestructible can also be harmed. Everything that makes France — material, spiritual and living — is for this same reason fragile. And we must not forget that."

Monday night's blaze collapsed the historic cathedral's roof and toppled its spire and might have burned priceless art.

So far, the fire is being investigated as an accident, possibly connected to a massive renovation project.

Paris prosecutor Rémy Heitz has already launched an investigation into the devastating blaze, which brought everyday Parisians and people around the world to tears.

"We are favoring the theory of an accident," Heitz told reporters outside Notre Dame Cathedral on Tuesday, promising a "long" and "complex" probe.

Pope Francis telephoned Macron to express his solidarity with France over the fire at Notre Dame, a Vatican spokesman said Tuesday.