A 25-year-old attacker invaded a preschool in southern Brazil and killed four children Wednesday with an axe-like weapon before turning himself in to police, authorities said.

"It is with immense sadness that I received the terrible news that the Good Shepherd preschool in Blumenau was invaded by a murderer who attacked children and employees. Unfortunately, four were killed," Santa Catarina state Governor Jorginho Mello said in a statement, declaring three days of mourning.

A source in his government confirmed to AFP the four victims were children, and said there were also four wounded.