With sweltering heat and tropical nights continuing for days in the nation, 17 people are presumed to have died from heat-related illnesses as of 4 p.m. Tuesday.

The Korea Disease Control and Prevention Agency(KDCA) disclosed the figure as it said three more people had died from such illnesses overnight.

Heat-related illness refers to acute conditions that develop due to high temperatures, with symptoms such as headache, dizziness, muscle cramps, and fatigue after prolonged exposure to heat.

The cumulative tally of heat-related illness cases this year grew by 210 from Monday to one-thousand-810. 

The agency estimated that the number of such cases had climbed by more than 100 every single day this month except for one day. 

32-and-a-half percent of people with such illnesses were seniors aged 65 or older and 79-point-five percent of the cases had occurred outdoors, including workplaces or farmlands.