A fire ripped through Copenhagen's Old Stock Exchange, one of the Danish capital's most famous landmarks, on Tuesday, engulfing its spire which collapsed in a scene reminiscent of the 2019 blaze at Paris' Notre-Dame Cathedral.

Emergency services, employees from the Danish Chamber of Commerce, including its CEO Brian Mikkelsen, and even passers-by were seen carrying large paintings away from the building in a race to save historic artefacts from the flames.

A video showed the flaming spire breaking in half as it tumbled down, sending a large part crashing to the ground next to a fire truck.

"Everybody is crying at the Danish Chamber of Commerce right now. It's their workplace, but also their history," Mikkelsen told reporters, shaking his head in disbelief.

"It's our cultural heritage that I'm looking at. It's 400 years that have shaped Danish cultural history and the society we live in today."

Denmark's National Museum sent 25 employees to the scene to help evacuate cultural artefacts and paintings, it said on X.

Video from local media showed people sitting on the ground outside the building, looking through paper catalogues listing and depicting the artefacts inside.

"We are saving everything we possibly can," Copenhagen fire department chief Jakob Vedsted Andersen told reporters.

Among the works saved were paintings by Denmark's Peder Severin Kroyer, a renowned 19th century impressionist.

Rescued items would be sent to Denmark's National Museum for examination, its head of collection storage and curation Camilla Jul Bastholm told Reuters.

The historic building, whose spire was shaped as the tails of four dragons intertwined, had been under renovation and clad in scaffolding when the fire broke out.

Parts of the roof had collapsed and the fire spread to several floors of the building, the fire service said, adding the firefighting operation would continue through the night.

There were no reports of injuries, police said, and it was not immediately clear what caused the blaze. (Reuters)