Notre-Dame's rector says he will close the burned-out Paris cathedral for up to six years.
Bishop Patrick Chauvet acknowledged that the famed monument would close down for "five to six years" as he spoke with local business owners on Wednesday, two days after a blaze torched the roof of the cathedral and brought down its spire.
Chauvet said "a segment of the cathedral has been very weakened" by the devastating fire. He did not elaborate which section he was talking about.
He added it was unclear what the church's 67 employees would be doing in the future.
Meanwhile, the French prime minister announced an international architects' competition to rebuild the cathedral's spire.
Edouard Philippe said the competition aims at "giving Notre-Dame a spire adapted to technologies and challenges of our times".
He said authorities have no estimate yet of the total cost of the renovation work.
French president Emmanuel Macron said on Tuesday that he wants the cathedral to be rebuilt in five years.
"This is obviously a huge challenge, a historic responsibility," he said.
The Paris prosecutor's office said investigators looking into the causes of the fire have still not been able to look inside the cathedral, as it remains unsafe.
Investigators will continue with interviews on Wednesday, saying the inquiry will go on until prosecutors uncover "the truth and identify the origin" of the blaze.
On Tuesday, investigators spoke with around 30 witnesses, including employees of companies involved in the church's restoration and security personnel.
Pope Francis told his weekly audience at St. Peter's Square of his sadness over the fire, in the seat of the Paris archdiocese.
The pope said on Wednesday that "I take this opportunity to express to the Paris diocesan community, all Parisians and the entire French population my great affection and my closeness after the fire in Notre-Dame Cathedral."
Addressing those gathered, the Pope said, "I was very sad and I feel very close to all of you."
He expressed "the gratitude of the whole church to those who did their utmost to save the Basilica, also risking their lives".
The Pope on Tuesday sent a telegram of condolences to Paris Archbishop Michel Aupetitand and phoned French President Emmanuel Macron to express his solidarity.