PARIS (NYT NEWS SERVICE ).- Notre Dame Cathedral in Paris will not hold Christmas services this week for the first time in over two centuries, as workers continue to shore up the fragile building after a devastating fire.

The 850-year-old cathedral has been closed to the public since a blaze tore through the structure in April, destroying a latticework of ancient timbers in its roof, sending the spire crashing down and spreading tons of toxic dust around Paris.

Records show that Christmas Masses have been celebrated at Notre Dame every year since at least 1803, after the cathedral was handed back to the Roman Catholic Church after the French Revolution, according to André Finot, a spokesman for the cathedral.

Finot said that the cathedral’s rector would instead hold this year’s Christmas service at the Église St.-Germain l’Auxerrois, a church near the Louvre where Notre Dame’s religious services have been relocated since the fire.

“It’s very hard for everyone; it’s yet another blow,” Finot said by telephone Monday.

President Emmanuel Macron of France vowed after the fire that Notre Dame would be rebuilt in five years, a tight deadline that authorities are sticking to so far.

Jean-Louis Georgelin, an army general nominated by Macron to lead the task force in charge of reconstruction, promised this month that a religious service would be held inside Notre Dame on April 16, 2024, exactly five years after the fire, to “celebrate the work that will have been done.”

Recovery efforts continue at the cathedral, which was added in October to the 2020 World Monuments Watch, a biennial list of cultural heritage sites that are in urgent need of conservation.

Authorities caution that Notre Dame is in an extremely precarious state and in need of constant monitoring to ensure parts of it do not collapse. The vault is still punctured by gaping holes, and the flying buttresses are propped up by giant wooden blocks.

But the most urgent threat to Notre Dame is thousands of scaffolding tubes — remnants of renovation work from before the fire — that were welded together by the blaze, creating a mass of twisted metal of roughly 250 tons that is weighing down on the structure.

Workers are currently erecting a 200-foot crane that will loom above the cathedral to help finalize the operations needed to stabilize that welded scaffolding.

New scaffolding is also being assembled. Workers will then use that perch to carefully cut the welded tubes and remove them one by one. Those operations are scheduled to start in February.

“The workers are very motivated,” said Finot, the cathedral spokesman. “Everyone is working relentlessly. They are really putting their heart into it.”

The exact cause of the fire is not yet known. Investigators are focusing on the possibility of a short circuit in the electrified bells of the spire or in the elevators that had been set up on the old scaffolding. They are also considering cigarette butts, which were found on the scaffolding, apparently left by workers.

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