Kim Jong-un’s sister has attacked US-led efforts to remove North Korea’s nuclear weapons.

Kim Yo-jong, a politician and diplomat, warned on Wednesday that her country’s status as a nuclear power is permanent and called any suggestion it could give up its weapons of mass destruction a “daydream”.

Her remarks came after the top diplomats of South Korea, Japan and the United States issued a statement on the sidelines of a Nato meeting last week in which they “reaffirmed their resolute commitment to the complete denuclearisation” of the isolated state.

Kim insisted that any external discussions of denuclearisation constitute “the most hostile act” and amount to a denial of her country’s sovereignty claiming the country’s goals for nuclear weapons expansion are enshrined in its constitution.

In comments to state media, she said: “It only fully exposed the uneasiness of the US, Japan and the ROK [Republic of Korea], in a desperate plight of having to talk about denuclearisation in chorus.

“If the US and its vassal forces continue to insist on anachronistic denuclearisation… it will only give unlimited justness and justification to the advance of the DPRK [North Korea] aspiring after the building of the strongest nuclear force for self-defence,” she said.

She said North Korea’s nuclear weapons status can “never be reversed by any physical strength or sly artifice.”