Three people were killed and 17 injured when a helium cylinder exploded inside a gift shop in New Cairo on Thursday evening.
Egypt's Health Ministry said the explosion triggered a fire inside the shop on the ground floor of Arabella Plaza Mall. Civil defence teams brought the blaze under control.
The facades of several neighbouring shops were damaged, the Interior Ministry said. It described the fire as limited.
Eight ambulances were sent to the scene, Health Ministry spokesman Hossam Abdel Ghaffar said. Eleven injured people were taken to New Cairo Specialised Hospital, and six others were transferred to nearby hospitals for emergency treatment and checks. The ministry said it was continuing to monitor their condition.
Initial reports about the blast were contradictory, with some accounts saying a lift had fallen or collapsed inside the mall. The Interior Ministry later denied the reports.
Egyptian prosecutors have opened an investigation into the circumstances and cause of the explosion.
Helium is commonly used by party and gift shops to inflate balloons. Unlike other gases such as propane or butane, helium is non-flammable. However, helium is typically stored in cylinders under high pressure, meaning cylinders can become dangerous if they are damaged, exposed to excessive heat or pressure, or improperly stored or handled.
It was not immediately clear whether any of these factors played a role in Thursday's explosion.
