The blaze was contained six hours after firefighters were called to an apartment complex near the intersection of 63rd and Jefferson streets around 2:15 a.m.
At least two firefighters suffered minor injuries while battling the blaze, KYW-TV reported.
Original report: Officials said the fire broke out about 2:15 a.m. at the Overbrook Gardens apartments, according to KYW-TV. At least two firefighters suffered minor injuries, authorities said.
About 50 people have been displaced by the fire, WPVI reported.
WPVI's Jeannette Reyes tweeted just before 7 a.m. that fire officials said they are "nowhere near done" battling the blaze and can't get inside the building because it may collapse.
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