More than 65 firefighters are battling an apartment fire in Melbourne's Spencer Street.
Crews were called just before 5am on Monday and the incident was quickly upgraded after the building was noted to have combustible cladding.
Paramedics have treated a man for smoke inhalation and Spencer Street is blocked in both directions with people being urged to stay clear of the area.
One resident said it was "pretty scary".
"The alarm just went off. I thought it is within our apartment but then I opened up the alleyway and it was the whole building. I just immediately took my cat with me. It was pretty scary. I was very panicked," she told the Nine Network.
The fire was deemed under control just before 7am and crews will remain on scene for some time, an MFB spokeswoman said.
The cause is yet to be established.