TOKYO – Three cities in central Japan recorded 40 degrees Celsius on Tuesday, officially marking the country's first "kokushobi," or "cruelly hot day," according to the country's weather agency.

As scorching heat gripped wide areas of Japan, Tajimi and Gujo in Gifu prefecture logged temperatures of 40.3 degrees Celsius and 40.0 C, respectively, while the mercury in Toyoda in Aichi prefecture rose to 40.1 C, the Japan Meteorological Agency (JMA) said.

In April, the JMA introduced the term "kokushobi," which refers to days when temperatures reach 40 C, to more effectively warn the public of extreme heat.

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Of the country's 914 observation points, 731 had reported maximum temperatures of 30 C or higher as of 3 pm local time, with 272 qualifying as "moshobi," which translates as "extremely hot day," excluding those separately classified as "kokushobi."

Weather officials said temperatures are expected to remain high in many parts of the country from Wednesday onward and urged the public to take precautions against heat-related illness.