It's unclear what caused the fire or what the condition of the firefighter is at this time. 

By: KDKA-TV News Staff

PITTSBURGH (KDKA) — A raging fire broke out in Pittsburgh’s Mt. Oliver neighborhood overnight.

Firefighters raced to put out flames attacking a home along Penn Avenue just before 1:00 a.m. Tuesday as the blaze spread to another home.

A Pittsburgh firefighter was transported to the hospital. Public Safety officials say he is in stable condition.

It’s unclear what caused the fire.

Stay with KDKA for more on this developing story.