An explosion leveled a two-story apartment building in this southern city early Saturday, killing at least seven people, firefighters said.

One person, an elderly man, was missing in the 3 a.m. blast, believed to have been caused by a gas leak.

A couple and their two children were among the dead, along with three members of another family who lived in the building. At least six residents were injured.

The explosion reduced the building to a pile of rubble, damaging nearby cars and hurling mattresses onto the street outside.

Gas blasts are not uncommon in Italy, where many people use canisters of gas to cook meals and heat homes.

In November 1999, 67 people were killed in a gas explosion in a six-story apartment building in Foggia (search).