Four members of a family were gunned down over the weekend outside the Mexican Pacific resort city of Acapulco by unidentified individuals, media reports said.
A man shot twice in the chest is listed in serious condition following Sunday's shooting, the Novedades de Acapulco newspaper reported.
One of the dead is a 34-year-old woman who was six months' pregnant, the daily said, adding that the motive for the killings has not been determined.
The murders occurred in Ampliacion Lazaro Cardenas, a neighborhood on the outskirts of Acapulco.
The Citizens Council for Public Safety and Criminal Justice said in a report issued in February that Acapulco was the world's second most violent city, with 142 homicides per 100,000 residents, trailing only San Pedro Sula, Honduras.
Acapulco, one of Mexico's most famous tourist destinations, has been plagued by drug-related violence in recent years. EFE