This article was reproduced with the kind permission
of the British Broadcasting Corporation
30 November 2007, 09:59 GMT
Police and fire crews led about 30 people to safety from the four-storey block in Whitehouse Street at about 0340 GMT. No-one was injured.
Grampian Police said later it appeared to have been suspicious.
A spokesman said: "Fortunately the families in the tenement were alerted by an automatic smoke alarm and the fire service was on the scene quickly."
A joint police and Grampian Fire and Rescue Service investigation has been launched.
Det Insp Andy Imray said: "The joint Grampian Police and Grampian Fire and Rescue investigation which is under way has established that there would appear to be suspicious circumstances. Enquiries are ongoing.
"We shall be carrying out house-to-house enquiries in the block and the local area.
"We are appealing to anyone who may have seen anything suspicious or unusual in the vicinity of the block of flats to contact us. We shall also be checking CCTV from the area."
Anyone with information has been asked to contact Grampian Police on 0845 600 5700 or Crimestoppers on 0800 555 111 .