Japan's government has urged people in Tokyo and its surrounding area to use less electricity on Monday, as it warned that supplies will be strained as the country faces a heatwave.
In a statement on Sunday, the ministry said that excess generating capacity for electricity was expected to drop to 3.7% on Monday afternoon in Tokyo and eight surrounding prefectures. It views a buffer of 3% as necessary for stable power supply.
The government asked people to turn off unnecessary lights for three hours from 15:00 Tokyo time (07:00 BST) while "properly using air conditioning and hydrating during hot hours".
"If there is an increase in demand and sudden supply troubles, the reserve margin will fall below the minimum required of 3%," it said.
Earlier this month, the Japanese government called on households and companies to save as much electricity as possible during its summer season from July to September.
Over the weekend, the Japanese city of Isesaki, which is 85 kilometres northwest of Tokyo, recorded the highest temperature that the country has ever seen in June.
Meanwhile, Japanese public broadcaster NHK reported that 46 people in Tokyo had been taken to hospital for suspected heatstroke, as of Sunday afternoon.
It also said a 94-year-old man in the nearby Kawagoe city was suspected to have died from the condition.
The news comes after Australian officials urged households in New South Wales - a state which includes the country's biggest city Sydney - to switch off their lights in the face of an energy crisis. Restrictions on the Australian wholesale energy market were lifted late last week.