Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, has warned that South Korea will have to pay a "dear price" for sending propaganda leaflets across the border.

In a statement carried by the North's state-run Korean Central News Agency (KCNA) on Sunday, Kim said that various kinds of propaganda leaflets and dirty things sent by South Korea fell in many areas near the southern border and even in the deep area of North Korea on Saturday. 

Kim said that North Korea strongly denounces the "shameful and dirty" acts of South Korea, who scattered anti-North Korea propaganda leaflets again in disregard of the North's repeated warnings.

Kim added that the inviolable territory of North Korea is being polluted, and much labor had to be used in disposing of these wastes.

She then warned that South Korea will have to pay a dear price, saying that there is a limit to their patience.

The KCNA disclosed a related photo showing a fallen balloon carrying leaflets, snacks, medicine and children's nutritional supplements.