A fire broke out in a hospital on Rome’s outskirts, killing at least three people and forcing the overnight evacuation of the smoke-filled facility and its patients, officials said Saturday.

Patients in intensive care at St. John the Evangelist hospital in Tivoli were transferred immediately to other hospitals via ambulance, the Tivoli mayor’s office said in a statement. Less-critical patients were moved into a nearby municipal gymnasium and then transferred to other facilities.

The governor of the Lazio region, Francesco Rocca, said from the scene that three people were killed and an investigation would determine the cause of the blaze. He acknowledged there were “notable delays” in updating Italy’s aging hospitals with sprinkler systems and other fire safety infrastructure.

The fire department initially said four people were killed after the blaze broke out late Friday. Italian news reports said the confusion arose because a body, already in the hospital morgue, was initially counted among the fire victims.

Video released by the fire department showed fire crews on ladders trying to reach the upper floors of the hospital to get to patients as smoke billowed out. Rocca, the governor, praised fire crews and the civil protection agency for the “truly exceptional” overnight operation to transfer the patients out of the building.

Premier Giorgia Meloni offered a note of condolences to the families of the victims.

Tivoli, which is located about 35 kilometers (20 miles) northeast of the center of Rome, is a popular tourist destination. It is best known for the archaeological sites of Villa d’Este and Villa Adriana, both of which are UNESCO World Heritage Sites.