The number of people taken to hospital by ambulance for suspected heatstroke symptoms in Tokyo in June was the highest for the month in at least a decade.
The mercury topped 35 degrees Celsius for the sixth straight day on Thursday in central Tokyo.
The capital's firefighting authorities say 294 people ranging from 6 to 97 years of age were rushed to the hospital for suspected heatstroke symptoms on Thursday alone. The daily figure surpassed 200 for three days in a row.
Preliminary figures show that 1,517 people used an ambulance in June for apparent heatstroke, the highest for the month in at least a decade. The figure is about six times as many as in June last year.
Sixteen of them were in critical condition, while 42 others were seriously ill.
The Medical Examiner's Office in Tokyo says 11 people from their 40s to 90s died apparently from heatstroke in June.
Officials are calling on people to keep hydrated and take other precautions.