FLORISSANT, Mo. – Five people are hospitalized after an overnight fire at a Florissant nursing home.

The fire happened around 12:30 a.m. at the Bentwood Nursing and Rehab Center the 1500 block of Charbonier Road.

Crews with the Florissant Valley Fire Protection District were among the first to respond, calling for additional support to a second-alarm fire. Investigators say a sprinkler system held the fire in check before more crews arrived to the scene.

Firefighters rescued five people from the building, though all five are being treated at a hospital Saturday morning with unknown injuries. The Florissant Valley Fire Protection District and STL First Responder Canteen shared pictures of the response via Facebook.

Investigators have not yet disclosed what might have caused the fire. Agencies from Florissant, Hazelwood, Berkeley, Robertson, Black Jack, Ferguson and Christian Hospital all assisted at the scene Saturday morning.