“I take this opportunity to express my strong regret for the treacherous treatment of the South Korean authorities,” she said in a statement released by Pyongyang’s official KCNA news agency.

“The United States and South Korea will face a more serious security threat by ignoring our repeated warnings to push ahead with the dangerous war exercises.”

She also said continuing the drills exposed the hypocrisy of US offers to resume dialogue over the North’s nuclear weapons programme. She said there will not be stabilised peace on the Korean peninsula unless the US withdraws its troops and weapons in the South.

Kim Yo-jong said the North would “spur our efforts to further strengthen our national defence capabilities and [already] strong pre-emptive strike ability” so that it could swiftly respond to any kind of military action.

“The reality has proven that only practical deterrence, not words, can guarantee peace and security of the Korean peninsula, and that it is an imperative for us to build up power to strongly contain external threats,” she said.

Professor Yang Moo-jin of the University of North Korean Studies said the statement indicated the North would continue to demand the withdrawal of US troops but would not issue any military provocation in retaliation to the drills.

“Judging from this statement, the North is likely to strongly call for the withdrawal of US troops from the South if and when dialogue reopens,” Yang said.

In January, Kim Jong-un vowed during at a party congress to “further strengthen our nuclear deterrence”, offering an unusually detailed list of weapons that the North was developing.

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These included “ultramodern tactical nuclear weapons,” “hypersonic gliding-flight warheads”, “multi-warhead” missiles, military reconnaissance satellites, a nuclear-powered submarine, and land- and submarine-launched intercontinental ballistic missiles that use solid fuel.

Kim’s statement came as the US and South Korean militaries began their preliminary training on Tuesday in the run-up to next week’s yearly summertime exercise.

US Department of Defence spokesman Martin Meiners declined to comment on the North Korean statement and said it was against policy to comment on training.

“Combined training events are a ROK-US bilateral decision, and any decisions will be a mutual agreement,” he said, using the initials of South Korea’s official name.

Seoul and Washington are treaty allies, with the US stationing around 28,500 troops in the South to defend it against its nuclear-armed neighbour.

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They have previously scaled back their annual joint military exercises significantly to facilitate nuclear talks with Pyongyang.

The South’s dovish Moon is credited with brokering the first ever summit between North Korea and a sitting US president, in Singapore in June 2018.

But the North largely cut off contact with Seoul following the collapse of a second summit between Kim and former US president Donald Trump in Hanoi that left nuclear talks at a standstill.

Additional reporting by Associated Press, Reuters