An explosion tore through an apartment building Saturday in Iran's port city of Bandar Abbas, killing a 4-year-old girl as local media footage purportedly showed a security force member being carried out by rescuers.

The blast happened a day before a planned naval drill by Iran in the Strait of Hormuz, the narrow mouth of the Persian Gulf through which a fifth of all oil traded passes. The US military has warned Iran not to threaten its warships or commercial traffic in the strait, on which Bandar Abbas sits.