At least 21 people have been killed and 11 othrs are missing in South Korea's flooding, with more than 3,000 people displaced. (Photo: AFP)

The death toll from weeklong heavy rains in South Korea rose to 21 on Saturday, with the country's longest monsoon in seven years causing more flooding, landslides and evacuations, according to the country's Central Disaster and Safety Countermeasure Headquarters.

More than 3,000 people had been evacuated as of 6 a.m. local time on Saturday while eleven people went missing and seven others were injured, local officials reported, as rains battered the southern part of the Korean Peninsula. 

The torrential rain spread from the country's central region, including Seoul and its surrounding metropolitan area, to the southern region on Friday.

South Korean President Moon Jae-in on Friday designated seven cities and counties in the central region as special disaster zones, making them eligible for state support in recovery efforts.

A submerged park flooded by the Han River is seen in Seoul, South Korea, August 6, 2020. (Photo: Reuters)

A landslide occurred at Gokseong county in South Jeolla province Friday afternoon, leaving four dead and one missing.

The country's forestry agency has raised landslide warnings to its highest level in every region except the holiday island of Jeju.

About 8,439 hectares of farm land were swamped or buried, while 8,246 cases of property damages were reported including 3,605 private assets and 4,641 public facilities.

Houses, cattle shed, warehouses and agricultural plastic houses were flooded or destroyed, while roads, railways, bridges and water reservoirs were damaged.