One of Copenhagen’s oldest buildings is on fire and its famous spire has collapsed.

The fire that began on Tuesday in the copper roof of the 17th-century Old Stock Exchange, or Boersen, has now spread to much of the building, and parts of the roof have also collapsed, said firefighters’ spokesman Jakob Vedsted Andersen.

The fire was first reported at 7.30am.

“The extinguishing work is very difficult,” said Mr Vedsted Andersen, adding that there are parts of the building that the firefighters cannot enter because it is too dangerous.

The building, that was once Denmark’s financial centre and is situated next to the Christiansborg Palace where the parliament sits, is a popular tourist attraction.

Its distinctive spire, in the shape of the tails of four dragons entwined together, reached a height of 56 metres (184 feet).

Huge billows of smoke rose over downtown Copenhagen and people were seen rushing inside the building to save paintings. Danish media reported that an annex of the parliament was being evacuated.

Police and firefighters were at work outside the building, which was encased in scaffolding. Ambulances were at the scene but there were no reports of casualties.

Members of an army unit were seen being deployed to cordon off the area, and the Danish Emergency Management Agency was also helping.

Danish culture minister Jakon Engel-Schmidt said it was “touching” to see how passers-by helped emergency services “to save art treasures and iconic images from the burning building”.

The roof, masonry, sandstone and spire of Boersen — built in 1615 and considered a leading example of Dutch Renaissance style in Denmark — was being renovated, said the Danish Chamber of Commerce which moved into the building after Copenhagen’s stock exchange left in 1974.

The chamber’s head, Brian Mikkelsen, was among those helping to carry paintings out of the building.

“It is a national disaster,” Mr Mikkelsen said.

King Frederik wrote on Instagram that “they woke up to a sad sight” of “an important part of our architectural heritage” being destroyed by the flames.

Prime Minister Mette Frederiksen wrote that “irreplaceable cultural heritage” and “a piece of Danish history is on fire”.

“It hurts to see,” Ms Frederiksen wrote on Instagram.

The adjacent Christiansborg Palace has burned down on several occasions, and most recently in 1990 a fire broke out in an annex of the Danish parliament, known as Proviantgaarden. However, the Old Stock Exchange survived unscathed.

That annex, which lies in the block behind the Old Stock Exchange, was evacuated as a precaution, as were different ministries in the street behind the burning building.

Beside housing the Chamber of Commerce, the Old Stock Exchange is used for gala dinners, conferences, parties and other events.

Police said on the social media site X, formerly Twitter, that a main road in Copenhagen was closed and people should expect the area to be cordoned off for some time.

The cause of the fire was not immediately known.