The influential sister of North Korean leader Kim Jong Un has said her country is willing to resume talks with South Korea if conditions are met, indicating it wants Seoul to persuade Washington to relax crippling economic sanctions.

Kim Yo Jong’s statement came days after North Korea performed its first missile tests in six months, which some experts said were intended to show it will keep boosting its weapons arsenal if the US-led sanctions continue while nuclear diplomacy remains stalled.

She offered the talks while mentioning South Korean President Moon Jae-in’s call, in a speech at the UN General Assembly, for a political declaration to end the 1950-53 Korean War as a way to bring peace to the peninsula.

“Smiling a forced smile, reading the declaration of the termination of the war, and having photos taken could be essential for somebody, but I think that they would hold no water and would change nothing, given the existing inequality, serious contradiction therefrom and hostilities,” Kim Yo Jong said in the statement carried by state media.

She said North Korea is willing to hold “constructive” talks with South Korea to discuss how to improve and repair strained ties if the South stops provoking the North with hostile policies, far-fetched assertions and double standards.

South Korea’s Unification Ministry said it is carefully reviewing her statement, and will continue efforts to restore ties.

The US-led sanctions have been toughened following North Korea’s provocative run of nuclear and missile tests in 2016-17, and Kim Jong Un has said the sanctions, the coronavirus pandemic and natural disasters were causing the “worst-ever” crisis in North Korea.

Earlier this year, he warned he would enlarge the country’s nuclear arsenal if the US refused to abandon its “hostile policy” towards North Korea.

North Korea and the US are still technically at war because the Korean War ended with an armistice, not a peace treaty. Pyongyang has consistently wanted to sign a peace treaty to formally end the war as a step towards improved relations.

Some experts say a treaty could allow North Korea to demand that the US withdraw its 28,500 troops in South Korea and ease the sanctions.

Both Koreas called for an end-of-war declaration and a peace treaty during a period of diplomacy with the US that began in 2018. There was speculation that then president Donald Trump might announce the war’s end in early 2019 to convince Mr Kim to commit to denuclearisation.

No announcement was made as the talks reached a stalemate after Mr Trump rejected Mr Kim’s calls for the lifting of toughened sanctions in exchange for limited denuclearisation steps.

Kim Yo Jong’s offer for talks was a stark contrast to a blunt statement issued by a senior North Korean diplomat earlier on Friday that the end-of-war declaration could be a “smokescreen” covering up hostile US policies.

Last week, North Korea conducted its first cruise and ballistic missile tests since March, demonstrating its ability to launch attacks on South Korea and Japan, two key US allies where a total of 80,000 American soldiers are stationed.

But Pyongyang is maintaining a moratorium on nuclear tests and launches of long-range missiles that directly target the American homeland, a sign that it wants to keep chances for future diplomacy with Washington alive.