The dead bodies of a 3-year-old boy and his 2-year-old sister were discovered Friday in a house in a farm of a village in Voronezh Oblast (province) of Russia, Novosti Voronezha reported.

According to preliminary data, the children had died due to carbon monoxide poisoning.

Their parents had gone out, leaving the youngsters behind in a room with an old metal stove.

The parents of these kids are Armenian citizens who had come to Russia in April, and they are in the process of immigrants’ registration.

The prosecutor’s office is considering the matter of opening a criminal case into this incident.