Miscellaneous blackouts left thousands of households sweltering without air conditioning in several Korean cities Sunday night, amid heat wave warnings.

About 260 households in an apartment building in Ilsan, Gyeonggi Province, lost power for an hour and a half on Monday at midnight.

According to the state-run Korea Electric Power Corp., the blackout was caused by trees that had grown over the summer and caused power lines to touch each other.

About 960 households in Deogyang, Gyeonggi Province, also had a blackout on Sunday, at 9 p.m.

Three people had to be rescued by firefighters in an elevator. The power was restored within an hour after fixing a circuit breaker.

In addition, 850 households Busanjin-gu, Busan had power outages for over five hours on Sunday 9:30 p.m. caused by a power overload leading to the breakdown of the circuit breaker, according to Kepco.

And 800 households in two apartment buildings in Hongcheon, Gangwon Province, suffered a blackout for 45 minutes because the transformer caught on fire, possibly due to overheating, according to the firefighters on Sunday.

High temperatures also caused a fire on a vehicle loaded with stainless steel in Buk-gu, Daegu, on Sunday 5 p.m. Hyundai Department Store in Daegu also suffered a sprinkler malfunction as temperatures in an indoor pipe reached 70 degrees Celsius.

According to the Korea Centers for Disease Control and Prevention there were a total of 180 patients hospitalized due to the heat from July 8 to July 14 which is a steep increase from 52 patients from July 1 to July 7.

Korean Meteorological Administration has issued heat wave warnings in 19 cities and provinces nationwide on Monday.

By Chyung Eun-ju (ejchyung@heraldcorp.com)