Fuerza Pública officers detained a U.S. man when they entered a Goicoechea dwelling late Tuesday.
They said they were acting on complaints from neighbors that children there were living in dangerous conditions.
The police identified the man who was detained by the last name of Amador, but the nature of the crime with which he is accused was not available.
Police said they found three tots, 4, 6 and 9, and a baby. The living quarters had windows that were covered with black plastic and protected by razor wire.
Police said that the living quarters were in a bad state but did not clarify. The children were placed in the custody of the Patronato Nacional de la Infancia, the child welfare agency.