Auto body shop on Brydges Street. (Google Maps)

Firefighters found one person unresponsive while battling a commercial fire on Brydges Street Thursday morning.

Crews were called to the scene around 6:30 a.m. after neighbours reported seeing flames from the building at 1122 Brydges.

Once on scene crews quickly confirmed that there were flames coming from the business and began attacking the fire.

Fire crews discovered a 46-year-old man on the second floor of the building unresponsive with life-threatening injuries.

"We did a primary, secondary search and at that time we found a person unresponsive, and we were able to remove them and put them in the care of EMS paramedics," says London Fire Department Platoon Chief Colin Shewell.

Fire officials say that EMS and firefighters worked together to revive the person.

He was transported to hospital and remains in critical condition, according to London police.

Firefighters had the fire knocked down by 7 a.m.

"Searching a large building in a timely manner is always a complex operation," says Shewell. "Encountering heavy smoke does make things very difficult."

Officials could not confirm if the fire was considered suspicious however London police and the Ontario Fire Marshal's Office have been notified and will be involved in the investigation.

Fire crews will be on scene for most of the day.

Damages are set at $100,000.