South Korea's President Lee Jae Myung declared six districts as special disaster zones on Tuesday after days of torrential rains left a trail of destruction in parts of the country.

Thousands of people were evacuated and some airlifted by helicopter, as a torrential storm tore through buildings in the nation’s southern and western provinces.

Torrential rains in South Korea over five days have caused 17 deaths and left 11 people missing, officials report.

The National Weather Service (NWS) has sent out alerts for extreme heat warnings, watches and advisories to millions of people across the South and parts of the Midwest, as a "heat dome" is expected to increase temperatures and humidity levels in those areas through the rest of the week.