North Korea rebuked Washington on Thursday for criticising its decision to cut communication links with Seoul, warning it to stay out of inter-Korean affairs if it wanted to ensure a smooth presidential election.

In a statement carried by the state-run Korean Central News Agency (KCNA), a senior North Korean foreign ministry official slammed the “double-dealing attitudes” of the US as “disgusting”.

Department of US Affairs director-general Kwon Jong-gun said Washington should “hold its tongue and mind its internal affairs first” if it wanted to avoid experiencing a “hair-raiser” and ensure the “easy holding” of November’s presidential vote.

The implicit threat comes just a day before the two-year anniversary of the landmark summit in Singapore where Kim Jong-un shook hands with Donald Trump, becoming the first North Korean leader to meet a sitting US president.

Negotiations over the North’s nuclear programme have been deadlocked since the collapse of a second Trump-Kim meeting in Hanoi last year over what Pyongyang would be willing to give up in exchange for sanctions relief.

Analysts say it has taken no substantive steps towards giving up its weapons but the impasse has left Pyongyang frustrated over the lack of concessions.

It has increasingly turned its anger towards Seoul rather than Washington, carrying out a series of weapons tests in recent months.

Since last week it has issued a series of vitriolic denunciations of the South, and on Tuesday announced it was cutting all official communication links with its neighbour.

The US State Department said it was “disappointed” by the decision.

Seoul and Washington are security allies and the US stations 28,500 troops in the South to protect it from its neighbour.

Pyongyang is subject to multiple UN Security Council sanctions over its banned weapons programmes but has carried out a series of tests in recent months – often describing them as multiple launch rocket systems, although Japan and the US have called them ballistic missiles.

Meanwhile, South Korea on Wednesday said it would take legal action against two defector groups for sending anti-Pyongyang leaflets across the border, after the North ramped up its threats over the campaigns.

North Korea has issued a series of vitriolic denunciations of the South since last week over activists sending anti-Pyongyang leaflets across the border.

The leaflets – usually attached to hot air balloons or floated in bottles – criticise the North Korean leader over human rights abuses and his nuclear ambitions.

The two groups of North Korean defectors had “violated an agreement between the leaders of the North and the South and created tension”, Seoul’s unification ministry added in a statement.

It said it would file a legal complaint with the police against them for violating a law on inter-Korean cooperation, and also begin a process to retract their licences.

The leaflet campaigns have long been a thorny issue between the two Koreas, but analysts said such legal action could spark an outcry over the possible infringement of the right to freedom of expression.

Officials in Seoul said last week they will consider a ban on leaflet launches just hours after a statement on the campaigns from Kim Yo-jong, the powerful younger sister and key adviser to the North Korean leader.

Calling the defectors “human scum” and “rubbish-like mongrel dogs” who betrayed their homeland, she said it was “time to bring their owners to account” – referring to the South Korean government.

After threatening to scrap a military pact with Seoul and close a liaison office – where activities were already suspended – this week she ordered all communication links cut with South Korea.

The move further raised tensions, with inter-Korean ties at a standstill despite three summits between Kim and the South’s President Moon Jae-in in 2018.

The two sides remain technically at war after Korean War hostilities ended with an armistice in 1953 that was never replaced with a peace treaty.