Mohammad Taqi Ashubi, the head of Gilan University of Medical Sciences, confirmed the fatalities at the Ghaem Hospital, explaining that 8 of the victims were in the intensive care unit.
The fire started at around 1:30 am local time (22:00 GMT, Monday), which was fully contained by firefighters.
142 patients who were hospitalized were transferred to other medical centers, according to the officials at the hospital.
Chief Justice of Gilan province, Esmaeil Sadeghi Niarki, said officials are investigating the case to find out the cause of the incident.