The incident which did not claim any lives occurred Thursday night at about 22.00 after the schools electricity grid caught fire due to an overload.
None of the girls were burned, Mohammad-Hossein Ramasht told the state-run news agency Fars on Friday.
Altogether 78 girls were taken to hospital, mostly due to breathing in too much smoke and some due to injuries after coming in contact with glass.
Eight of the students still remain in hospital.