North Korea has said it is cutting off all communication channels with South Korea.

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

When South Korean officials tried to contact their North Korean counterparts via several channels after the North’s announcement, the North Koreans did not answer, according to the South Korean government.

North Korea has cut communications in the past — not replying to South Korean phone calls or faxes — and then restored those channels when tensions eased. North Korea has been accused at times of deliberately creating tensions to bolster internal unity or to signal its frustration over a lack of progress in nuclear talks with Washington.

North KoreaNorth Korea’s relations with South Korea and the US have been strained of late (Korean Central News Agency/Korea News Service/AP)

In its announcement, North Korea said the move was a response to South Korea’s failure to stop activists from floating anti-Pyongyang leaflets across their border.

“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.

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

For years, conservative South Korean activists, including North Korean defectors living in the South, have floated huge balloons into North Korea carrying leaflets criticising leader Kim Jong Un over his nuclear ambitions and human rights record. The leafleting has sometimes triggered a furious response from North Korea, which bristles at any attempt to undermine its leadership.

South Korea has typically let activists launch such balloons, citing their rights to freedom of speech, but has halted some attempts when North Korean warnings appeared to be serious. In 2014, North Korean troops opened fire at propaganda balloons flying toward their territory, triggering an exchange of fire that caused no known causalities.

North Korea began taking issue with the leafleting again last week.

Mr Kim’s sister Kim Yo Jong called defectors involved in recent leafleting “human scum” and “mongrel dogs”, and she threatened to permanently shut down a liaison office and a jointly run factory park, both in the North, as well as nullify a 2018 inter-Korean military agreement that had aimed to reduce tensions.

North Korea’s latest moves will further set back South Korean President Moon Jae-in’s push for inter-Korean reconciliation.