A man and woman are hospitalized after a house they were in exploded in the Milwaukee suburb of Glendale, causing fire damage at several nearby houses and injuring several others who helped at the scene.

The Milwaukee Journal Sentinel reported Sunday that investigators don't yet know what caused the Saturday blast. The two people, both inside the house, have not been identified but are described as father and daughter. The home's owner is an 88-year-old man.

A spokeswoman for Columbia St. Mary's said the man is in serious condition and the woman asked her condition not be released.

A neighbor, a passer-by and two other people suffered injuries while helping the victims get out.

Two police officers were treated for smoke inhalation and a fire fighter for heat exhaustion.