PHILADELPHIA -

A partial collapse of a six-story building under construction on the main campus of Temple University in Philadelphia injured one worker and trapped several others Thursday afternoon, officials said.

The injured construction worker is hospitalized in stable condition, said a spokesman for the city fire department.

The collapse happened on the fourth floor, said Executive Fire Chief Richard Davison, adding that firefighters rescued several workers who were stuck on the upper floors.

Pictures and video of the building showed fallen metal girders on one side of the building.

Davison says it wasn't immediately clear what caused the collapse.