Cars and pedestrians pass a flooded road in Seoul's Gangnam District, Monday night. Yonhap

The heaviest rainfall in 80 years has pounded Seoul and surrounding regions, leaving eight people dead and six others missing, as well as flooding homes, vehicles, buildings and subway stations, officials said Tuesday.

Parts of Seoul, the western port city of Incheon and Gyeonggi Province that surrounds Seoul received heavy rains of over 100 millimeters per hour Monday night, with per-hour precipitation in Seoul's Dongjak district surpassing 141.5 mm at one point, the highest downpour per hour since 1942.

The Korea Meteorological Administration said up to 300 mm of more rain is forecast for the capital area through Thursday, with southern Gyeonggi Province likely to see rains surpassing 350 mm.

The downpours left five people dead and four others missing in Seoul, while in Gyeonggi Province, three had died and two others had gone missing as of 11 a.m., according to the government.

Nine people sustained injuries in Gyeonggi Province and 391 people from 230 households in the capital area were left homeless and took shelter in schools and other public facilities.

In Seoul's Gwanak district, three family members ― a woman in her 40s, her sister and the sister's teenage daughter ― reported they were trapped in a submerged semi-basement home at 9:07 p.m. Monday but were later found dead.

In Dongjak, a ward office employee in his 60s died of what was believed to be electric shocks at 6:50 p.m. during clean-up work after a roadside tree fell down due to the rain.

An additional person was killed at 5:40 p.m. in a submerged home in the district.