The mercury in many areas of eastern and western Japan topped 38 degrees Celsius on Saturday.

A daytime high of 38.6 degrees was recorded in Isesaki City, Gunma Prefecture. Yorii Town in Saitama Prefecture logged 38.5 degrees, and Fukushima City registered 38.2 degrees.

The Japan Meteorological Agency says the intense heat will continue through Friday next week.

The agency and the Environment Ministry warn that risks of developing heatstroke will be extremely high on Sunday. Heatstroke alerts have been issued for 32 prefectures.

Environment Ministry officials say the death toll from heatstroke tends to surge during heat waves. An increasing number of people have been coming down with heatstroke, and some of them have died.

They advise people to avoid going out unless absolutely necessary, use air-conditioning appropriately and keep hydrated.