A firefighter was injured early Monday battling a blaze in a vacant building in Frankford, officials said.

The injuries were described a minor and the firefighter was expected to be released following treatment at Hahnemann University Hospital.

The fire in the top two floors of the vacant apartment building in the 1200 block of Arrott Street in the Northwood neighborhood was reported about 1 a.m. and it took firefighters more than three hours to bring it under control.

Eight neighbors were forced from their nearby homes and put aboard a SEPTA bus to keep warm while firefighters tackled the fire in subfreezing temperatures.

The cause of the fire is under investigation.