Montreal police are investigating five cases of arson over two days.
Early Wednesday morning, police were called in to investigate a fire in a carpet store and at a paint company.
In the latest incident, firefighters responded to a fire at a carpet store in the city's Ahuntsic district at around 3:50 a.m. on Wednesday.
One of the windows at the building on l'Acadie Boulevard near De Louvain Street was broken and there was evidence the fire was criminal, said Const. Raphaël Bergeron.
The fire caused significant damage to the store, which is located in a strip mall.
Three hours earlier firefighters responded to a call at a paint company on Edison Street in the city's Anjou district.
Bergeron said someone had thrown a Molotov cocktail through the window.
The fire was quickly contained and did not cause significant damage, he said.
"At this point we don't have any suspects, we are going to have to see if … they had received any sort of threats over the last couple of days," said Bergeron.
On Monday night, Molotov cocktail attacks were reported at three Montreal eateries.
Authorities have so far refused to link the incidents.
The arson cases follow a string of 18 Molotov cocktails targeting cafés between last September and January.
Last month, police announced five people had been charged in connection with the attacks.
All of the suspects had ties to street gangs, though police did not speculate on a motive for the attacks.