Dela Paz said the exit door in the back of the store was padlocked, blocking the escape route.
Police say the store did not have a 
permit to sell fireworks [Reuters]
He said the store did not have a permit to sell fireworks and that police had recently launched a crackdown on dealers selling fireworks inside malls and stores in order to prevent accidents.
"But they put up some displays in the afternoon," dela Paz told The Associated Press. "Apparently that's where the fire started."
He said police were looking for the owner but could not locate him.
Firefighters took more than three hours to bring the blaze under control. It is not yet clear what sparked the fire.
Firecrackers and other pyrotechnics are extremely popular during the Christmas holiday period in the predominantly Christian Philippines.
However, safety measures are often ignored and accidents involving cheap, poorly-made and improperly stored fireworks are common.