Fire investigators are probing the cause of a blaze that destroyed several homes under construction in Ajax.

Firefighters were called to a burning townhouse complex near Rossland Road East and Salem Road North at about 9:40 p.m. Monday.

It took crews about 90 minutes to bring the blaze under control.

During that time, police evacuated a townhouse complex across the street as a precaution. About 20 people were forced from their homes.

Durham Regional Police said the construction project was nearing completion because the building was framed and shingles and windows were installed.

A damage estimate wasn't available, but it will likely be in the hundreds of thousands.

No injuries were reported.

Durham Regional Police and the Office of the Fire Marshal are investigating the cause of the blaze.