SEOUL - The influential sister of North Korean leader Kim Jong Un slammed US President Joe Biden for making nuclear threats, saying it marked the “dotage of the old” and would be met by a boost in her country’s atomic arsenal.

Ms Kim Yo Jong’s comments, released by the state media on Saturday, mark the first official reaction from North Korea to a meeting this week in Washington between Mr Biden and South Korean President Yoon Suk-yeol to boost their deterrence against Pyongyang, and include a rare mention of the US President in its propaganda apparatus.

She called the “Washington Declaration” reached between Mr Biden and Mr Yoon “a product of the vicious hostile policy towards the DPRK which reflected the most antagonistic and aggressive will of action”, the official Korean Central News Agency (KCNA) reported, referring to the country by its formal name.

Ms Kim, who has been used as the face of the pressure campaign against the United States and South Korea, added that while the two countries bring more nuclear assets into the region, North Korea will respond by boosting its arsenal “in direct proportion to it”.

South Korea’s Unification Ministry denounced Ms Kim’s claims as “far-fetched” and showing the low level of the regime, Yonhap News reported.

It remains to be seen if her words will be marked by a ramping up of provocations by Pyongyang, which has been firing ballistic missiles at a blistering pace.

It is seeking to enhance its ability to deliver a credible nuclear strike to the US mainland and the two allies in Asia who host the bulk of America’s military personnel in the region – South Korea and Japan.

Mr Biden stressed in his meeting with Mr Yoon that a North Korean nuclear attack on the US and its allies would be the end of Mr Kim’s regime, as he announced new efforts with South Korea to counter Pyongyang’s nuclear build-up.

Mr Yoon was rewarded with a greater say in how America deploys its nuclear umbrella and assurances it would be used to retaliate against a North Korean strike.

KCNA has mentioned Mr Biden by name on its English-language service only six times previously in a database search that goes back to 2000, usually in insult-laced barbs such as calling him “an imbecile bereft of elementary quality as a human being” in a 2019 dispatch.

At the same time, it was lavishing praise on then President Donald Trump, who met three times with Mr Kim. While the meetings were historic, they resulted in no concrete measures to wind down North Korea’s nuclear arsenal, which only grows larger and more lethal.

Ms Kim also made a dig at Mr Biden, as he seeks re-election in 2024.

“Of course, it may be called a nonsense of the old without future who will not be responsible for the security and prospect of the United States at all and considers it to be burdensome to stand only two years of his term of office in the future,” she said.

North Korea has already fired 17 ballistic missiles in 2023, which included three intercontinental ballistic missiles designed to deliver a nuclear warhead to the US mainland. The country fired more than 70 ballistic missiles in 2022, a record for the state.

North Korea has demonstrated its missiles could fly as far as the US, but there are questions as to whether the warheads would be able to stay intact long enough to reach their targets. BLOOMBERG