Multiple people died and many more were injured after a fire broke out at an assisted living center in the city of Fall River, Massachusetts on Sunday, a spokesperson for the U.S. state’s fire department said on Monday.

“We are withholding the exact number pending updates on some patients’ conditions. This is a terrible tragedy for the City of Fall River and the families involved. Our hearts are with them this morning,” Massachusetts fire department spokesperson Jake Wark told Reuters in an emailed statement.

Wark said that about 50 firefighters responded to the incident and tackled the fire at the Gabriel House assisted living facility.

Firefighters rescued numerous occupants, but multiple residents were declared dead at the scene, while many others were transported to hospitals, he added.

The origin and cause of the fire are under investigation.