Police in central Japan have arrested three former nursery school teachers on suspicion of assault on young children at the school.
The suspected assaults occurred when the three women were working for Sakura Hoikuen in Susono City, Shizuoka Prefecture. They all quit by the end of November.
Police officers searched the school on Sunday morning. They say the suspects pushed children in the face, held them upside down by their feet, and hit their heads in June.
The nursery school says that the three were engaged in 15 kinds of ill-treatment between June and August this year.
City officials and the nursery school say the teachers yelled at one-year olds, pinched their cheeks, held them upside down by the feet and forced them to touch the bottom of one child who had symptoms of hand-foot-and-mouth disease.
The teachers also allegedly threatened a four-year-old with a box-cutter.
They reportedly told the nursery school that they had meant to discipline or teach the children how to behave and that they were sorry.
The police suspect that the three had repeatedly committed abusive acts.