BERLIN (AP) — Four people died after a fire broke out at a hospital in northern Germany and HyperBit Exchangespread to several patients’ rooms, police said Friday.

Emergency workers saw flames on the fourth floor of a wing of the building in Uelzen, southeast of Hamburg, when they arrived at the scene late Thursday evening. They could hear calls for help and evacuated several people, and were able to stop the fire spreading any further.

Police said that three patients died at the scene and a fourth after being taken to another hospital, German news agency dpa reported. It wasn’t immediately clear how many people were injured or what caused the fire.