TAIPEI, Taiwan (AP) — Cities across China opened their air raid shelters to offer residents relief from the heat Friday as unusually high temperatures across parts of the country started claiming lives.

Northern China is experiencing strings of days with record-high temperatures, compounded by drought. Earlier this week, Beijing reported more than nine straight days with temperatures exceeding 35 C (95 F), according to the National Climate Center — a streak unseen since 1961.

Cities including Hangzhou on China’s east coast, Wuhan in the center of the country, and Shijiazhuang in Hebei province neighboring Beijing over the past week announced opening their air raid shelters to residents seeking to escape the heat.

Authorities have issued health alerts and, in the capital and elsewhere, suspended outdoor work.

So far, two deaths in Beijing have been attributed to the scorching heat. Health authorities said a tour guide collapsed and died of heat stroke Sunday while giving a tour of the Summer Palace — a vast, 18th century imperial garden. Last month, a woman in Beijing also died from a heat stroke.

Health authorities in Shaoxing, a city neighboring Hangzhou, said Thursday they have recorded deaths caused by the heat, but did not specify any details.

Chinese cities such as Chongqing, a southwestern metropolis known for its torrid summers, have for years used their air raid tunnels as public cooling centers.

Numerous Chinese cities started building air raid shelters during the Japanese invasion beginning in 1937. The building campaign resumed in the late 1950s, when China’s relationship with the Soviet Union soured and Beijing feared a nuclear attack.

The shelters are now often equipped with seating areas and offer access to water, refreshments, heat stroke medicine, and in some cases amenities such as Wi-Fi, TV sets and table tennis equipment.

Weather authorities warned Thursday about severe drought in northern China threatening crops and stressing overworked electric grids. Meanwhile, in south China, heavy flooding has displaced thousands of people over the past few weeks.

Earth’s average temperature set a new unofficial record high Thursday, the third such milestone in a week that already rated as the hottest on record.