Fire investigators have not ruled out arson in a fiery west-end blaze that destroyed a row of townhouses under construction Monday night.

The fire spread to nearby power lines and transformers, shutting down power in the Bloor Street and Mill Road in Etobicoke area for hours. Power was fully restored Tuesday morning.

At one point, the fire was so powerful, flames were reportedly shooting 100 feet into the air. Some reported seeing the fire all the way from Highway 427.

Fire crews were called to the scene around 9 p.m. and soon, about 100 firefighters and 24 fire trucks were helping battle the blaze. It took them about two hours to get the fire under control but in the end, nine town homes were completely destroyed.

Fire Chief Bill Stewart said it was a difficult blaze to battle.

"The embers were blowing off the buildings and into the surrounding area," he told CTV News.

The fire also drew a crowd of curious spectators from the neighbourhood who heard the commotion and wanted to see what was going on.

Some of them were getting too close, trying to capture images of the fire with their video cameras. Firefighters warned them to move back as at one point, several explosions were heard in the distance.

Investigators are looking into how the blaze was able to spread so quickly.

Officials said there have been more than 40 deliberately set fires across Toronto this year, and are wondering whether the same suspect is involved.

"A lot of what's going on in the city are garbage fires, backyard garages, things like that," said Jim Fisher, of the Ontario Fire Marshal's office.

"Serial arsonists do progress. I mean it's a known fact. They start off with garbage cans and work to abandoned buildings, garages and unfortunately to occupied dwellings and things like that."

With a report from CTV's Austin Delaney