Police are investigating a fire at an apartment building in Fitzroy which occurred earlier this morning.
Emergency services were called to the Nicholson Street address just after 4am.
No one was injured but approximately 20 people were evacuated from surrounding units.
The fire is being treated as suspicious and a crime scene has been established.
An arson chemist will examine the scene later today to determine the exact cause of the fire.
Investigators urge anyone who witnessed the incident or with information to contact Crime Stoppers on 1800 333 000 or file a confidential report online at www.crimestoppersvic.com.au