Three firefighters required medical treatment after battling a two-alarm blaze that damaged three rowhomes and left about two dozen residents displaced Monday evening in South Philadelphia, the fire department reported.

Firefighters responded around 5 p.m. to the 1600 block on South Fifth Street and found a three-story house with heavy fire showing on all three floors. The fire spread to neighboring homes and a second alarm was struck.

The fire was declared under control around 6:20 p.m., but crews remained to put out hot spots.

Three firefighters received treatment at the scene and were taken to a hospital for further care.

The American Red Cross late Monday night said it was providing temporary lodging and emergency assistance for 10 people displaced by the fire.

The cause of the fire was under investigation.