By Dan Wing and Natasha Brown

PHILADELPHIA (CBS) -- A Center City fire forces authorities to close several roadways during this evening's commute.

Officials say firefighters were on the scene in the 1800 block of Moravian Street at 5:45pm, but didn't see the fire from the outside of the building, however once inside they found the blaze on the 2nd and 3rd floors, and it was quickly placed under control.

"We had one minor firefighter injury, non-life threatening. That firefighter was transported to Hahnemann hospital. We have four-displaced citizens. They are being cared for by family members and the landlord," said Deputy Chief Michael Wahl of the city's fire prevention division.

Wahl says the cause of the fire remains under investigation.