South Korea issued today (Sunday) its first heat wave warning in history under a new alert system introduced this year, urging residents to stop outdoor activities and make sure to stay in cool places.

According to Agence France-Presse, under the new system, a heat wave warning is issued when the perceived temperature is expected to reach at least 38 or 39 degrees Celsius, even for just one day.

Officials said the new warning system was introduced to better handle the increasing heat waves in South Korea, which have become longer and more intense.

The head of the Korea Meteorological Administration, Lee Mi-son, announced in a press conference 'issuing an emergency heat wave warning at 10:00 a.m. today (01:00 GMT) for two cities in North Gyeongsang Province in the south of the country, namely Gyeongsan and Pohang.'

She added: 'It is the first time this warning has been issued since the system took effect.'

Lee explained that the affected areas experienced temperatures that reached the warning criteria over the weekend.

She said the heat wave warning does not just mean a severe rise in temperatures, 'but indicates conditions in which even healthy individuals face an increased risk of serious health damage, including heat-related illnesses and death.'

She clarified that when this warning is issued, people engaging in outdoor activities should immediately stop and head to cool places.

She also urged residents to 'make sure there are no people or animals inside vehicles.'