Twenty children and a nurse who was trying to help babies were injured.
Eighteen injured are stable while two injured babies are in a critical condition.
All casualties are born in 2006 and 2007.
Firefighters arrived at the scene quickly and managed to put the blaze under control in ten minutes' time.
When they came, one baby was already dead and another two died in hospital soon.
All the victims died of suffocation.
An investigation is under way. According to some preliminary findings, the fire was caused by electrical fault.