Even as officials continued to assess the damage and search for a cause in the massive fire that completely destroyed its roof of Notre Dame Cathedral, French President Emmanuel Macron said in a televised national address to his country Tuesday evening that he wants to see the 13th century basilica rebuilt within five years.
"We will rebuild Notre Dame Cathedral even more beautiful," Macron said.
He thanked the firefighters who battled the blaze for hours Monday night and into Tuesday before bringing the inferno under control, and expressed appreciation for the donations pouring in from around the world.
"We have so much to rebuild," said Macron. He added that France has endured revolutions and wars -- and "we've always rebuilt."
Earlier, Andrew Finot, head of communications for Notre Dame, said he got a brief look inside the decimated sanctuary and reported the "entire roof has disappeared" and there is standing water on the floor from the battle waged by firefighters to extinguish the inferno.
When asked to estimate how long it will be before the cathedral is reopened to the public, Finot told ABC News, "I don't know, maybe not before three years I believe. We need to create a new roof."
He said 80 percent of the priceless artifacts in the sanctuary, including the Crown of Thorns purportedly worn by Jesus when he was crucified, were saved by a team comprised of firefighters, cathedral staff and members of the Ministry of Culture, who arrived within 30 minutes of the fire starting on Monday afternoon. The artifacts, according to Finot, were placed in a vehicle and driven to City Hall.
Though much of its roof is collapsed and interior decimated, the charred walls of the Notre Dame Cathedral remain standing over Paris' Seine River.
Valérie Pécresse, president of the Île-de-France region that encompasses Paris, said it is a "miracle" that the walls of the cathedral are still standing.
That is a testament to the "face-to-face" battle firefighters waged through the night to quash a massive blaze that ripped through the 13th Century basilica and prompted a global response to help rebuild, Pécresse said in an interview on ABC's "Good Morning America" on Tuesday.
"When you see it from the outside, it's still standing, and that is quite a miracle," Pécresse said told GMA host Robin Roberts.
Pécresse said firefighters fought the blaze through the night, saving the main sanctuary and the cathedral's historic bell towers. The first photos released from inside showed the altar intact with a gold crucifix still hanging above it.
"We are terribly, tremendously grateful to the firemen of Paris because they really saved the cathedral," Pécresse said.
Still, she said watching the inferno tear through the church was "like tearing our hearts apart because the cathedral is the heart of Paris."
But when asked what she wants the world to know about Notre Dame in the aftermath of the devastating fire, Pécresse said, "Tell them that the cathedral is still standing."
The blaze broke out at 6:50 p.m. local time Monday and quickly spread along the roof of the cathedral, which was undergoing a $170 million renovation was partially encased in scaffolding. It took firefighters hours to bring the fire under control as much of nave was constructed of ancient timbers that fueled the flame and came crashing through the roof.
The cause of the fire is under investigation. Remy Heitz, the Paris public prosecutor, said Tuesday 50 people are working on the "long" and "complex" probe of the fire, but there is no evidence to suggest the blaze was deliberately set. Investigators are leaning towards the theory it was an accident that sparked the inferno, he added.
French President Emmanuel Macron expressed sadness at the sight of the 850-year-old building's demise but vowed to rebuild it at a news conference outside the cathedral.
Responding to Macron's call for help, people from across France and the world began pledging money to help in the reconstruction.
At least 300 million euros ($339 million) have been pledged so far to help rebuild the Notre Dame Cathedral.
French billionaire Bernard Arnault and his conglomerate LVMH pledged 200 million euros, according to The Associated Press, and François-Henri Pinault, another French billionaire, said he and his family would donate 100 million euros, according to BuzzFeed.
Before the fire, an estimated investment of 150 million euros over three decades likely would've been required for restoration work on the massive church, a group called Friends of Notre Dame told ABC News. Total repair costs following the fire aren't yet known.
Pécresse said she informed the archbishop of Paris, Michel Aupetit, that the government set aside 10 million euros (about $11.3 million) in emergency funds to rebuild the cathedral.
"But we'll need hundreds of millions of euros to rebuild, maybe more, because 2,800 square meters of roof has burned and also ... the big tower of the cathedral has burned too, so we really need to rebuild and it's going to be very costly," Pécresse said on GMA. "So seeing all the people of the world telling us that they want to subscribe, it's really moving for us and this support is really amazing."
Construction on Notre Dame began in 1163 and lasted over a century. It officially was completed in 1345.
Krupali Krusche, an architecture professor at the University of Notre Dame in South Bend, Indiana, told ABC News it may take five to seven years for the cathedral just to recover from the blaze.
"The original building took over 100 years to actually come together, piece by piece," Krusche said. "It will be done. But a recent project in Europe of that scale has taken up to 10 years to produce."
Although largely famous for its ornate exterior stonework, most of the cathedral's interior was wood, which fed the flames like a "cooker," she added. But even masonry that survived may be terribly damaged after 500 firefighters fought the blaze.
"We will rebuild because it is what the French people expect because it is what our history deserves," Macron said at the news conference. "Because it is our profound destiny."
Other developments pertaining to the fire include:
-- 10 a.m. EDT: French Junior Interior Minister Laurent Nunez said investigators identified weaknesses in the cathedral structure that needs securing, "notably in the vault and the north transept pinion," an area of the nave that forms a cross.
-- 11 a.m. EDT: Photos of relics saved from the cathedral were released, including the Crown of Thorns, purportedly worn by Jesus when he was crucified, and the Tunic of Saint Louis, which supposedly belong to King Louis IX.
-- 12 p.m. EDT: The White House released a new statement saying President Donald Trump offered his condolences to Macron on behalf of the American people.
"The United States stands with French citizens, the city of Paris, and the millions of visitors from around the world who have sought solace in that iconic structure," the statement reads. "The Cathedral has served as a spiritual home for almost a millennium, and we are saddened to witness the damage to this architectural masterpiece. Notre Dame will continue to serve as a symbol of France, including its freedom of religion and democracy. France is the oldest ally of the United States, and we remember with grateful hearts the tolling of Notre Dame’s bells on September 12, 2001, in solemn recognition of the tragic September 11th attacks on American soil. Those bells will sound again. We stand with France today and offer our assistance in the rehabilitation of this irreplaceable symbol of Western civilization. Vive la France!"
-- 12:05 p.m. EDT: New wire service photos released show the extensive damage inside the main sanctuary of Notre Dame, including charred wooden beams that fell from the ceiling and landed in front of the altar.
-- 12:43 p.m. EDT: Bells at Westminster Abbey in London tolled in support of Notre Dame Cathedral and the people of France.
-- 2 p.m. EDT: In a televised speech to his nation, Macron said he wants the cathedral rebuilt in five years.
ABC News' David Rind and David Wright contributed to this report.