Fire department spokesman Sergio Vasquez says the girls were in pajamas when their bodies were spotted before dawn Wednesday by passers-by who summoned authorities. He says the girls appeared to be between 6 and 12 years old.
Vasquez says police are investigating whether the girls were strangled. He says one was holding rosary beads.
Police also found the bodies of two women in their 30s at two other locations in the same district Wednesday.
Vasquez says both women had been shot to death.
He says police are trying to determine if the four deaths are related.
None of the victims has been identified.