A five-alarm fire engulfed the top floor of a Bronx apartment building on Friday night, injuring 10 people — two of them seriously — and prompting more than 200 firefighters to respond, the authorities said.

Nine of the 10 people injured were firefighters, according to Jason Powell, a Fire Department spokesman, who said that one of those seriously injured was a firefighter. None of the injuries were life-threatening, he said.

The fire was reported at 8:15 p.m. at 1555 Grand Concourse, a 150-unit apartment building in the Mount Eden section of the Bronx, fire officials said. It became a five-alarm fire at 9:46 p.m., with 46 fire units and 210 firefighters responding to the scene, the authorities said.

The cause of the fire is still under investigation but is not considered suspicious, according to the Fire Department.