Writer and Manchester tour guide Jonathan Schofield said: “It’s a shock.”
“I’ve walked past for years and years. I’ve guided it, talked about it and now it’s a shell.
“For this to go up in such a dramatic way, it is a shame.”
Pat Karney, the city council’s city centre manager, said the building was “a piece of Manchester” and “a very famous building”.
“It’s incredibly dangerous to have fires in city centres. We’ll have to learn lessons.
“You can’t ignore the dangers. The buildings are too close to each other.”
Manchester City Council leader Bev Craig said the authority had been working closely with emergency services and evacuated residents were being supported at a nearby rest centre.
She said: “A cordon remains in place in the area and we thank people for taking fire service advice to avoid the area while crews continue to work at the site.
“Those living nearby should continue to keep windows and doors shut to avoid smoke.”