Police in central Japan have raided a nursery school where childcare workers have allegedly abused young children. Authorities cite acts such as holding their charges upside down by their feet.

The search on Sakura Hoikuen in Susono City, Shizuoka Prefecture, began on Sunday morning.

The nursery school says that three women teachers there were engaged in 15 kinds of ill-treatment between June and August this year. The city government has acknowledged those acts would constitute abuse.

City officials and the nursery school say the teachers yelled at one-year olds, pinched their cheeks, held them upside down by their 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 act and that they were sorry. All three quit by the end of November.

The city authorities ordered the nursery school in August to identify the children who were abused. But officials say the school has not provided complete information.

Police are looking at assault charges in the investigation.

Officials of the prefectural and city governments are also investigating how the school is run and how children were ill-treated in detail.