Two people died and hundreds were treated in hospital after a weekend heatwave swept over Japan, officials and reports said.
A woman aged 74 collapsed while working in a greenhouse in the eastern prefecture of Chiba on Saturday and was later pronounced dead.
In Ibaraki, also in the east of the country, a woman, 61, was found collapsed in her garden and died.
Yesterday, a 76-year-old man was taken to hospital unconscious in Sera, in the western prefecture of Hiroshima, after collapsing near a river bank.
"He is suspected of having a heatstroke," an ambulance worker said.
There were unconfirmed reports that the man had been working in rice paddies before collapsing.
More than 300 people were treated at hospitals on Saturday alone, the public broadcaster said as temperatures rose past 30 degrees Celsius in many towns across the nation.
The mercury hit 33 degrees in central Tokyo by mid-afternoon yesterday with over 36 degrees recorded in Tatebayashi , north of the capital.
The country's power companies had already warned that they would find it tough to meet the seasonal demand peaks. All of Japan's nuclear reactors remain offline as regulators examine plants for defects highlighted by the disaster at the Fukushima plant in March 2011.
Work is still under way at the site to get four crippled reactors under control and to clean up the radiation.