SEOUL - South Korea's national rail company on Wednesday suspended some regular routes and slowed bullet trains because of heavy rain in the central region that caused flooding and landslides.

The city of Gunsan received nearly 100mm of rain within an hour early on Wednesday and a number of areas in the central region received precipitation of more than 200mm a day, according to the weather agency.

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The Ministry of Interior reported four people died and also said property, roads and infrastructure had been heavily damaged.

There are landslide warnings for more than 50 areas and more than 3,500 people have been displaced, it said.

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Korail, the national rail service, said the Saemaeul and Mugungwha trains have been suspended on six central regional routes, with some service halted for a few hours and some until midnight.

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The KTX bullet trains were operating but were running at reduced speeds through some areas, Korail said.

The month of July is annually the monsoon season in the country but it has experienced extreme weather in the summer months in recent years, which President Yoon Suk-yeol has said should be anticipated due to climate change.