North Korean youth and students march from the Pyongyang Youth Park Open-air Theatre to Kim Il Sung Square during a protest demonstration to denounce South Korean authorities policy against North Korea and defectors from the north, in Pyongyang, North Korea, Monday, June 8, 2020. AP

North Korea's anger at propaganda leaflets flown across the border from South Korea shows how sensitive the autocratic regime is to criticism of leader Kim Jong-un, especially at a time of economic difficulties deepened by the coronavirus and sanctions.

Pyongyang said earlier in the day it will cut off all phone lines with Seoul starting Tuesday noon, accusing Seoul of turning a blind eye to North Korean defectors and activists sending propaganda leaflets criticizing its leadership.

Branding leafleting as a hostile act, the North also vowed to treat the South as an "enemy."

"The disgusting riff-raff have committed hostile acts against the DPRK by taking advantage of the South Korean authorities' irresponsible stance and with their connivance," the Korean Central News Agency (KCNA) reported, using the acronym for the North's official name.