Tokyo, July 31 (IANS) Extreme heat continued to grip Japan on Monday, with the mercury already topping 35 degrees Celsius in many areas of the country's east and north, the country's weather agency said.

The Japan Meteorological Agency (JMA) said by 11:00 a.m., the temperature had reached 37.7 degrees in Hatoyama town in Saitama prefecture, near Tokyo, 37.1 degrees in Date city in Fukushima prefecture, and 35.1 degrees in central Tokyo, reports Xinhua news agency.

Officials warned that the risk of people developing heatstroke is extremely high, and issued alerts for Tokyo, Kyoto, and 17 other prefectures.

The JMA said that atmospheric conditions are expected to become unstable in northern and eastern Japan through Tuesday due to a cold air mass and the temperature rises during the daytime, warning against possible lightning, gusts, hail and torrential rain.