A heat wave warning remained in effect for most parts of South Korea on Sunday, the state weather agency said, with a sharp rise in heat-related deaths reported in the country's southern and other regions over the weekend.

Earlier in the day, the Korea Meteorological Administration (KMA) raised a heat wave advisory in some parts of Gyeonggi Province, which surrounds Seoul, and South Jeolla Province to a heat wave warning. The heat wave warning first went into effect for most parts of the country Tuesday.

Heat wave warnings are issued when the highest apparent temperature is expected to be 35 C or higher for more than two consecutive days or if major damage is anticipated from the heat.

Over the weekend, the number of deaths from scorching temperatures surged to 12, including those presumed to have died from the extreme heat, according to health authorities. From May 20 through Friday, three people were thought to have died from heat-related diseases.

On Saturday, four people, whose ages range from 70s to 90s, died while engaging in farming activities in North Gyeongsang Province. They are thought to have died from the extreme weather.

On the same day, South Gyeongsang Province reported two deaths from the heat wave -- a farmer in Miryang and another in Namhae.

Gyeonggi Province also reported two deaths -- in Yangpyeong and Anseong -- while North Chungcheong Province reported one death in Jecheon, the province's first fatality from the high temperatures.

In addition, a 70-something resident in Gunsan, North Jeolla Province, was found dead in the yard of his home. The authorities are trying to verify whether his death is attributable to the hot weather.

On Sunday, a man in his 80s was found dead in a field in Yecheon, while a 90-something man died on a street in Mungyeong.

The midday temperature rose to 35 C in Seoul, Daegu, Gangneung and Cheongju, while most of the country saw the mercury rise to 33 C.

The weather agency said the sensible temperatures in most regions of the country are expected to range from 33 C to 35 C for the time being as it calls on people to take extra care with their health during the heat wave.

The KMA advised the public to drink water frequently, refrain from outdoor activities and urged those working outside to stop working between 2 p.m. and 5 p.m.

Meanwhile, five people died by drowning in different locations over the weekend as they apparently went there to beat the heat.

Source: Yonhap News Agency