North Korean leader Kim Jong Un said his military should “thoroughly annihilate” the United States and South Korea if provoked, state media reported on Monday, after he vowed to boost national defences to cope with what he called an unprecedented US-led confrontation.

Mr Kim is expected to ramp up weapons tests in 2024 ahead of the US presidential election in November. Many experts believe he thinks his expanded nuclear arsenal will allow him to wrest US concessions if former president Donald Trump is re-elected.

In a five-day meeting of the ruling party last week, Mr Kim said he will launch three more military spy satellites, produce more nuclear materials and develop attack drones this year in what observers say is an attempt to increase his leverage in future diplomacy with the US.

In a meeting with commanding army officers on Sunday, he said it is urgent to sharpen “the treasured sword” to safeguard national security – an apparent reference to his country’s nuclear weapons programme.

He cited “the Us and other hostile forces’ military confrontation moves”, according to the official Korean Central News Agency.

Mr Kim stressed that “our army should deal a deadly blow to thoroughly annihilate them by mobilising all the toughest means and potentialities without moment’s hesitation” if they opt for military confrontation and provocations against North Korea, KCNA said.

In his New Year’s Day address on Monday, South Korean President Yoon Suk Yeol said he will strengthen his military’s pre-emptive strike, missile defence and retaliatory capabilities in response to the North Korean nuclear threat.

“The Republic of Korea is building genuine, lasting peace through strength, not a submissive peace that is dependent on the goodwill of the adversary,” he said, using South Korea’s official name.

At the party meeting, Mr Kim called South Korea “a hemiplegic malformation and colonial subordinate state” whose society is “tainted by Yankee culture”.

He said his military must use all available means including nuclear weapons to “suppress the whole territory of South Korea” in the event of a conflict.

In response, South Korea’s Defence Ministry warned that if North Korea attempts to use nuclear weapons, South Korean and US forces will punish it overwhelmingly, resulting in the end of the Kim government.

KCNA said North Korean officials held talks on Monday to implement an order by Mr Kim to disband or reform organisations handling relations with South Korea to “fundamentally change the principle and direction” of the North’s struggle against the South.

There was no immediate explanation of how that might alter inter-Korean relations, which have been stalled for an extended period.

Experts say small-scale military clashes between North and South Korea could happen this year along their heavily armed border. They say North Korea is also expected to test-launch intercontinental ballistic missiles capable of reaching the mainland US, and other major new weapons.

In 2018-19, Mr Kim met Mr Trump in three rounds of talks on North Korea’s expanding nuclear arsenal. The diplomacy fell apart after the US rejected Mr Kim’s offer to dismantle his main nuclear complex, a limited step, in exchange for extensive reductions in US-led sanctions.

Since 2022, North Korea has carried out more than 100 missile tests, prompting the US and South Korea to expand their joint military drills.

North Korea has also tried to strengthen its relationships with China and Russia, which blocked efforts by the US and its partners in the UN Security Council to toughen UN sanctions on North Korea over its weapons tests.

KCNA said Mr Kim and Chinese President Xi Jinping exchanged New Year’s Day messages on Monday on bolstering bilateral ties.

North Korea faces suspicions that it has supplied conventional arms for Russia’s war in Ukraine in return for sophisticated Russian technologies to enhance the North’s military programmes.

Estimates of the size of North Korea’s nuclear arsenal vary, ranging from about 20-30 bombs to more than 100.

Many foreign experts say North Korea still has some technological hurdles to overcome to produce functioning nuclear-armed ICBMs, though its shorter-range nuclear-capable missiles can reach South Korea and Japan.