AYER, Mass. (WHDH) -- A five-alarm fire tore through a three-story building in Ayer overnight, forcing residents to evacuate early Tuesday morning.

The fire started early in a commercial and residential building on Main Street in Ayer. Officials say they believe it started in a new restaurant that was set to open in about a week; it would have been called the Sidetrack Pub.

The fire chief says fire alarms in the building were working and that the contractor doing the renovations put a lot of money into fire protection systems for the new restaurant.

A Subway restaurant is on the first floor. Apartments are on the second and third floors. The fire chief says the fire spread fast.

“The building’s an old building; it went up the exterior walls into all floors,” Chief Robert Pedrazzi said.

Crews from several towns were called in to help but all firefighters were ordered to get out of the structure around 1 a.m. Tuesday.

Everyone inside was able to make it out safely. Seven adults and two children were displaced.