ZAMBOANGA — At least 27 people, including 19 police and other government personnel, were injured when a large pile of confiscated illegal fireworks exploded in a powerful blast in the southern Philippines, damaging houses, hotels and an international airport, officials said Tuesday.

Two of the victims of Monday afternoon's explosion were in serious condition in a hospital in the southern port city of Zamboanga, where the mayor ordered an investigation into why the planned controlled destruction of the fireworks by police ordnance experts turned into a massive blast.