The Office of the Ontario Fire Marshal and Halton police are investigating a suspicious fire that heavily damaged a more than 120-year-old church in northeast Burlington.

Burlington Fire was called to the Trinity Baptist Church at 4372 Appleby Line, just north of No. 2 Sideroad, around 1:18 a.m.

The first crews on scene saw visible flames in the southwest corner of the building that eventually extended up the wall and got into the attic, destroying the roof, said Deputy Fire Chief Ross Monteith.

No one was injured, but the original church building, built in 1890, was heavily damaged by the fire. Monteith said it was difficult for firefighters to navigate inside the old, tall building and at a certain point they had to refocus their efforts on saving the newer additions to the church, which escaped unscathed.

It's too early to know what caused the blaze or the dollar loss. However, Monteith said damage is likely in excess of $500,000.

Halton police spokesperson Sgt. Dana Nicholas confirmed the fire is considered suspicious.

The word "ISIS" is visible in spay paint on the building. Nicholas said police are aware of the graffiti, but added it's too early in the investigation to know if it's related to the fire.

At the height of the fire there were 40 firefighters on scene from 12 trucks. The rural area does not have hydrant access, so other fire crews from Milton and Hamilton shuttled water to the scene.

Fire crews remained on scene putting out hot spots until about 10 a.m., Monteith said.

Appleby Line was closed in the area throughout the morning and into the afternoon Wednesday.

According to the church's website, the Trinity Baptist congregation moved to the Appleby Line church in 1975.

Anyone with information is asked to contact Halton police at 905-825-4747 ext. 2316.