TOKYO - Japan is facing an unprecedented heat wave, with temperatures nearing 40 degrees Celsius in areas from Tokai to Kanto regions on Sunday.

The Japan Meteorological Agency (JMA) has issued heatstroke alerts for 26 prefectures, urging residents to take precautions against the potentially deadly heat.

With the relentless heat showing no signs of abating, daytime temperatures are expected to soar above degrees Celsius, marking the first time this year for Japan to see over 200 locations experience extreme heat.

On Sunday, the mercury in Tokyo is forecasted to reach 36°C, as many regions from Tokai to Kanto could see temperatures exceeding body temperature, according to the JMA

On Sunday, the mercury in Tokyo is forecasted to reach 36°C, as many regions from Tokai to Kanto could see temperatures exceeding body temperature, according to the JMA.

With temperatures in Maebashi and Chichibu predicted to hit 39°C, those in some inland areas of Kanto would potentially reach 40°C.

The heatwave has led to record number of heatstroke cases in many parts of the country. Two elderly residents in prefectures of Ehime and Tokushima were reported dead over heatstroke, while Tokyo reported 119 heat-related emergency cases on the same day, including three severe cases among the elderly.

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Authorities urged residents, especially elderly people and children, to use air conditioners appropriately, stay hydrated even when not thirsty, and avoid unnecessary outings and exercise.