COPENHAGEN: A huge fire on Tuesday devastated Copenhagen's 17th-century former stock exchange, toppling the historic building's landmark spire in front of horrified witnesses.

The 54m spire disappeared into flames at the Borsen building, which had been undergoing renovation, an AFP journalist saw.

"This is our Notre-Dame! This is a national treasure," emotional local resident, 45-year-old Elisabeth Moltke, told AFP as she watched the blaze.

"A lot of old Danish paintings, originals are in there. I've been in there several times and it's a magnificent building so it makes me feel very emotional."

The fire started at 7.30am local time (0530 GMT) under the red-brick building's copper roof, emergency services told reporters, as more than a hundred firefighters were dispatched to the scene.

The spire snapped and crashed down onto the street below.

Dramatic photographs showed orange flames and huge plumes of black smoke billowing from the rooftop.

Fire trucks surrounded the building, covered in scaffolding and wrapped in tarp and which today houses the Danish Chamber of Commerce.

It lies just a stone's throw from the country's Parliament and seat of government Christiansborg.

"It's a copper roof, and it's simply impossible to get under that roof, so the fire has plenty of time to build intensity," Jakob Vedsted Andersen, director of emergency services, told news agency Ritzau, adding that the fire had spread down into the building.

The Borsen building, commissioned by King Christian IV and built between 1619 and 1640, is one of Copenhagen's oldest and best known landmarks.

Housing a vast art collection, it was being renovated to celebrate its 400th anniversary.

"Terrifying images from Borsen this morning. Four hundred years of Danish cultural heritage going up in flames," Culture Minister Jakob Engel-Schmidt wrote in a post on the X social media platform.

The images recalled the disaster at Notre-Dame Cathedral in Paris, almost five years ago to the day it was gutted by a fire.

Onlookers could not hold back tears as they watched the devastation.

"I'm lost for words... It's a 400-year-old building that has survived all the other fires that burned Copenhagen down to the ground," said Carsten Lundberg, an employee at the Danish Chamber of Commerce.

"It's a dreadful loss," Lundberg told AFP adding that what was inside were "things that you cannot put a price on... Priceless paintings, statues..."

Engel-Schmidt said he had been moved to see employees, rescue workers and residents working to "rescue art treasures and iconic paintings from the burning building."

Images from the scene showed several people rescuing works of art, including a painting of the building.

Forces from the Danish military were also called to the scene, in particular to try to evacuate artworks.

"We are working hard to save our historical art from Borsen," the Chamber of Commerce said in a post to X.

Police said they had blocked off parts of the city centre as part of the fire-fighting efforts.

 -AFP