PHILADELPHIA (CBS) — An early morning fire forced people from their homes at a high-rise apartment building in Center City Philadelphia.

Flames broke out shortly before 6 a.m. Monday at the Embassy Apartments in the 2100 block of Walnut Street in Rittenhouse Square.

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Officials say the fire started in the back of the building on the exterior.

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Firefighters were able to get the fire under control in less than 30 minutes.

There were no reports of any injuries.

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The cause of the fire is under investigation.