A five-year-old boy died Thursday after being left behind in a school bus for hours on a hot summer day in the southwestern Japan prefecture of Fukuoka, police said.

Toma Kurakake was found unconscious in a school bus in the city of Nakama in the evening and later pronounced dead at a hospital, apparently due to dehydration, the police said.

When the boy did not come home on the bus as expected, his mother called the nursing school to report him missing. School staff found him collapsed inside a different bus, which had been used to pick children up in the morning and remained in the school's parking lot.

The bus driver was quoted by the police as saying, "I was aware of (the boy's) boarding, but thought he got off the bus," while admitting he did not confirm it at the time.

According to a local meteorological observatory, the temperature surpassed 33C in nearby Kitakyushu City at 11 a.m.

Kurakake's 59-year-old grandmother lamented the loss of the child, whom she described as a "cheerful, smart boy."

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