MONTREAL - Police have determined that a fire at a three-storey Rosemount apartment complex Monday morning was intentionally set and have started a manhunt for suspects.

The fire started shortly after 8 a.m. at 3915 Masson St. on the second floor of the building. It quickly spread to the third floor and tenants from all 26 units were forced out.

One tenant who escaped the building described the experience to CTV Montreal.

"It was like a boom, a big noise," said tenant Soosai Pillai. "I left the smoke coming from that corner of the apartment. There was smoke coming down the stairs and I smelled the smoke and I got ready and got out."

A supporting wall of a neighbouring building was also at risk of collapse because of the fire.

There were about some 60 firefighters on the scene.

No injuries were reported and the fire was under control in about an hour.

The cause of the blaze hasn't been determined.

Genevieve Dery, a spokeswoman for the Canadian Red Cross, said an undetermined number of people living in six of the building's apartments have been taken in by family.

Three people have been put up in hotels by the Red Cross for the next three days.

Montreal police Const. Daniel Lacoursiere said arson investigators were called in to help determine the cause of the fire.

"If it's arson or not and then they will meet with the people in the apartment building to ask if they saw or hear anything and if it matches with what they discovered in the apartment where the fire started," said Lacoursiere.

"Let's just say it gets the year off to a bad start for my residents," said owner Paul Rouleau.

Rouleau said he did not know of any suspicious or illicit activity in the building or any other potential reason that the building might have been targeted.

- with files from The Canadian Press