The Glasgow School of Art "will be saved" after it was gutted in a massive blaze, according to its director.
Construction experts have suggested the Mackintosh building could be so badly damaged, it would have to be torn down.
But Prof Tom Inns told BBC Scotland that experts have carried out an initial survey and he confirmed the shell of the building is intact.
"This building is not beyond saving - absolutely", he said. "It will be saved in some form."
And he spoke of his conviction that the Mack should continue as a working art school, rather than a museum.
On Tuesday afternoon, Glasgow City Council's building control team said it had now taken control of the site and would "significantly reduce" the cordon.
This means a number of businesses and residents will be allowed to return to their properties.
Firefighters have been at the scene of the blaze, which also devastated the nearby O2 ABC music venue, for more than 72 hours.
At its height, there were more than 120 firefighters involved in the operation.
It is the second time in four years that the art school has been damaged in a major fire.
The Mackintosh building was at the centre of a £35m restoration project when the blaze broke out on Friday night.
Prof Inns told BBC Scotland that drones have been flown over the site to assess its condition and he was certain it could be rebuilt.
"We have got very close to rebuilding it from the previous fire," he said.
"We have got a very experienced team now that understands this building intimately but rebuilding it is going to be a very, very complex process.
"We are going to have to stabilise the building, then we are going to have to think very, very carefully about what the strategy might be moving forward."
He added that he was hopeful that it would continue to be a base for creativity.
"In my mind, the Mackintosh building only works if it's got an art school inside it," he said. "It has to have creative activity inside it to be the Mackintosh building.
"However the building comes back in its physical state, it has to have that creative activity inside it or it's not complete as a building."
Muriel Gray, the head of the board of governors, said that when she was told about the fire, she thought it must be a "black joke".
"But it's not a joke sadly, just déjà vu," she said.
The broadcaster told BBC Scotland that, as she watched the fire burn, she feared they would be left with a "gap site".
"But actually once again the Mack confounds us," she said. "I think it's sending out a message it will not be defeated."
Despite the cordon around the affected buildings being reduced, council leader Susan Aitken said that as there remained a risk to public safety, a substantial exclusion zone would remain in place for the foreseeable future.
Business advisors will be based in Sauchiehall Street to help traders affected.
Ms Aitken said: "Our building control team has now assumed responsibility for the site of the Mackintosh Building and the other affected properties.
"The cordon that was around these properties will be reduced, which will help many of the businesses and residents that were evacuated in the early hours of Saturday morning.
"However, a substantial cordon will remain for the foreseeable future, as the condition of these buildings is assessed - and I understand that will be a significant worry to those still unable to get access."
She added: "This is a dynamic and complex situation; but we will work with residents and businesses to give them as much clarity as we can, when we can."
Earlier, in an interview on Good Morning Scotland, Ms Aitken said the local authority was focused on saving the historic landmark.
She said initial superficial assessments had been carried out by officials, including building control officers.
"Certainly I think the consensus is that there is hope and and we are certainly not writing off the Mackintosh building yet," she said.
"Our intention, our focus will be to try and save that building and finding a future for it, but it's very early days."
One expert has suggested the cost of restoring the building after the latest fire could be more than £100m.
When Ms Aitken was pressed on whether she was willing to back restoration at any cost, she replied: "It's far too early to start talking about cost.
"We have seen lots of figures flying about but they are purely speculative. There's no one who's able to put a price on this at the moment."
Building expert Billy Hare compared the blaze to that which gutted the building housing Victoria's nightclub on Sauchiehall Street in March.
The professor of construction management pointed out that the council very quickly took the decision to demolish that building.
But Ms Aitken said that decision was taken because it was unstable and in danger of "imminent collapse".
"That's not the case, we think, with the Mackintosh building at the moment," she said.
"Having said that, it is very early days. The initial assessments are that what remains of the building is largely structurally solid but it is really, really early days."
She said there was a consensus that the council should work with other organisations including the Scottish and UK governments to restore the building if it is possible.
Meanwhile, traders on Sauchiehall Street have warned that the fire could spell the end for some businesses in the area.
Donald MacLeod, the owner of the nearby Garage nightclub, said trade was already down as a result of roadworks connected to a planned regeneration of the area as part of the Glasgow City Deal.
He said the fire was a "hammer blow" to dozens of local traders. "They are bereft and looking for help," he said.
Many have been closed since Saturday as they are inside a safety cordon put in place by the fire service.
He said the roadworks had hit footfall and had a "calamitous" effect on some businesses, who fear the effect of the fire may be "terminal".
Ms Aitken will lead a meeting later with business representatives on the future of Sauchiehall Street in the wake of the fire.
She said businesses inside the cordon set up by the fire service are being invited to apply for zero-rating on business rates.
On Monday, fire investigators promised to find out what caused the blaze.
Assistant Chief Officer David McGown said a "comprehensive and professional" probe will be carried out.