South Korea ordered people living near rivers in its central region to evacuate homes on Thursday as heavy monsoon showers dumped more than 300 mm (12 inches) of rain, while warnings went out across a large swathe of the country, including the capital.
The rain caused cancellation of more than 24 flights at the Incheon international airport on the west coast, and also disrupted train services in Seoul, emergency authorities said.
The government was watching for sudden surges in rivers flowing from North Korea, urging vigilance against any landmines planted at the border by its neighbour that could get washed downstream.
South Korea's military has said it could not rule out the chance that the North planted more mines in recent weeks, fully aware of the likelihood of heavy rain.
"We're monitoring the water level in the main rivers shared by the South and the North in real time," a military spokesman, Lee Chang-hyun, told a briefing.
North Korea has ignored its neighbour's demand to be given notice when it opens floodgates at a large reservoir after a flash flood that killed six people in the South in 2009, caused by a surge in a river across the border.
Although July brings annual monsoon rain, summer months in recent years have seen weather extremes that President Yoon Suk Yeol has said should be anticipated as a result of climate change.
