COPENHAGEN, Denmark — Copenhagen's mayor said Thursday she contacted her Paris counterpart to see what could be learned from the reconstruction of the Notre Dame cathedral in the French capital, after a fire devastated the Danish city's 400-year-old stock exchange building.

Firefighters were still at the scene two days after a blaze destroyed half of Copenhagen's Old Stock Exchange, which dates from 1615, and collapsed its iconic dragon-tail spire.

The Danish Chamber of Commerce, which was headquartered in the Old Stock Exchange and owns the building, has said they want the building to be reconstructed. However, no decision has yet been made about who will finance a reconstruction, a project that would cost millions, if not billions of kroner (dollars) and take years.

Sophie Hæstorp Andersen, the Danish capital's mayor, told The Associated Press that she had been in touch with Paris Mayor Anne Hidalgo to discuss how the French handled the reconstruction of the Notre Dame cathedral after an April 2019 blaze ravaged the 800-year-old landmark. Its restoration is slated for completion this year.

Hidalgo gave ''some good inputs on how to move quickly, how Paris handled donations and the restoration which must be done fast," Hæstorp Andersen said.

''We stand before a huge task when it comes to rebuilding Boersen together with the Danish Chamber of Commerce ... but we know this can be done quickly,'' she said, using the stock exchange building's Danish name.

She added that Hidalgo has invited a Danish team to meet those behind the rebuilding of Notre Dame's spire.

Tuesday's blaze was believed to have started on the roof during renovations, but the cause remained unclear and police had yet to enter the burned part of the building to investigate.

Work continued Thursday to stabilize the building, with the Greater Copenhagen Fire Department saying they expect to be working at the scene of the fire for at least another day.

''The walls are very unstable,'' firefighter spokesman Tom Ole Simonsen said. Containers filled with concrete have been erected around the Old Stock Exchange to support it.

The copper roof had collapsed inside the shell of external walls and on Friday, they will try to remove the burned parts from inside the building with a huge crane, Simonsen said.

Although firefighters used ''millions'' of liters (gallons) of water, ''it still smolders and glows inside,'' Simonsen said. He added that the highest alarm was sounded Tuesday six minutes after the fire department was alerted.

Several streets around the charred building, including a main road running past it, will remained closed until Monday at least, Simonsen said.

When the fire engulfed the building on Tuesday, passers-by, Chamber of Commerce staff, police officers and firefighters raced inside the building to save its treasures. Many of the building's most valuable contents, which included irreplaceable paintings and other works of art, had been saved. Among them was the huge 1895 painting ''From Copenhagen Stock Exchange'' by Danish artist P.S. Krøyer, the Chamber of Commerce said.

The exchange, known for its green copper roof and distinctive 56-meter (184-foot) spire in the shape of four intertwined dragon tails, sits on the waterfront next to the Danish parliament.

The building is considered a leading example of the Dutch Renaissance architectural style in Denmark. The Chamber of Commerce moved into the building after Copenhagen's stock exchange left in 1974.

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This story corrects the spelling of French mayor's last name to Hidalgo instead of Hildago throughout.