North Korea said it will cut off all communication channels with South Korea at noon today as it escalates its pressure on the South for failing to stop activists from floating anti-Pyongyang leaflets across their tense border.

South Korea’s liberal government, which espouses greater ties with North Korea, repeated that it will work toward restoring peace on the Korean Peninsula in its response to the warning.

The North’s Korean Central News Agency said all cross-border communication lines will be cut off in “the first step of the determination to completely shut down all contact means with South Korea and get rid of unnecessary things.”

It said the decision was made by Kim Yo Jong, the powerful sister of leader Kim Jong Un, and Kim Yong Chol, a former hard-line military intelligence chief who Seoul believes was behind two 2010 attacks that killed 50 South Koreans.

“The South Korean authorities connived at the hostile acts against (North Korea) by the riff-raff, while trying to dodge heavy responsibility with nasty excuses,” KCNA said. “They should be forced to pay dearly for this.”

South Korean conservative activists, including North Korean defectors living in the South, for years have floated huge balloons into North Korea that carry leaflets criticizing Kim Jong Un over his nuclear ambitions and abysmal human rights record. The leafleting has long been a source of tensions between the Koreas since the North bristles at any attempt to undermine the Kim leadership.

Last week, Kim Yo Jong called the defectors “human scum” and “mongrel dogs” as the North also threatened to permanently shut down a liaison office and a jointly run factory park, as well as nullify a 2018 inter-Korean military agreement that had aimed to reduce tensions.

North Korean citizens have also participated recently in a series of mass rallies opposing the Seoul government, activities the North typically organizes in times of tensions with the outside world.

South Korea’s Unification Ministry, which handles relations with North Korea, said cross-border hotlines must be maintained as they are the basic means of communication between the two Koreas. It said the South Korean government will strive to promote peace while abiding by inter-Korean agreements.

Relations between the Koreas have been strained during a prolonged deadlock in broader nuclear diplomacy between Pyongyang and Washington. Some experts say North Korea may be deliberately creating tensions to bolster internal unity or launch a bigger provocation in the face of persistent U.S.-led sanctions.-AP

This undated file photo shows a South Korean officer using a military hotline with North Korea.

North Korea cuts Seoul military hotline