At least 12 people, including three firefighters, were injured in a five-alarm blaze at a building in Brooklyn Monday morning, fire officials said.

According to fire officials, the fire broke out in the two-story building at 96 Boerum Place shortly before 10:30 a.m.

Fire officials said nine firefighters were taken to area hospitals, and three civilians were treated on scene for injuries.

It took firefighters nearly three hours to get the fire under control.

The FDNY referred to the building as a "mixed-occupancy" building. An internet search indicated that a gym named "UFC Fit" is located at that address.

Fire marshals are investigating the cause.