Authorities say the cause of a blaze that burned through buildings in Melbourne's west and prompted a watch-and-act alert is being treated as suspicious.
Emergency services received multiple triple-0 calls about 4am about the fire at a party supplies store in Sunshine.
Fire Rescue Victoria's (FRV) acting assistant chief fire officer David McCurdy said crews arrived to find the building alight and the back of the store collapsed.
"It was a very intense fire," he said.
The fire spread along a shared roof line to a Cash Converters store, and also impacted the nearby Sunshine Fruit Market.
The fire was near the intersection of Clarke Street, Dawson Street and Devonshire Road, at the centre of Sunshine's bustling shopping district.
Mr McCurdy said there were signs of a break-in at the front, with investigators working out whether that was related to the fire at the rear of the building.
There were 21 FRV appliances called to the scene, with a watch-and-act alert issued about 7am for nearby residents.
The blaze was brought under control later in the morning and there were no reported injuries.
But Mr McCurdy said authorities were working to keep pedestrians away throughout the morning due to remaining smoke and the detection of asbestos in the building.
Police and firefighters said the cause was being treated as suspicious. Brimbank Crime Investigation Unit detectives are investigating the fire.
Victoria Police Senior Sergeant Gus Storer said a crime scene would remain in place until the cause of the fire was established.
"There's been significant damage caused to at least two premises," he said.
The state's Environment Protection Authority was also called to the scene.
"We're working with Melbourne Water to minimise firewater impacts on waterways including Stony Creek," the authority said.
Senior Sergeant Storer said while the streets were likely to have been quiet at 4am, police were urging anyone with information or dashcam footage to contact Crime Stoppers.
