At least three Argentines died when a shop suspected of illegally selling fireworks for New Year parties exploded on Friday evening, burying victims under tonnes of rubble, officials said.
Another 15 people were injured, some with serious burns, in the Buenos Aires suburb of Florencia Varela. Firefighters and rescuers clawed away at the collapsed building looking for survivors, local television showed.
"There was a smell of fireworks and the power of the explosion leads me to believe it was fireworks," the mayor of Florencia Varela, told local radio.
Local media said at least five people died, including a neighboring dentist, and up to five people were missing.
Every year police find many illegal fireworks factories in Argentina, often with little or no safety precautions.