North Korea’s leader Kim Jong Un is due to meet his South Korean counterpart for the third time later this month to discuss “practical measures” towards denuclearisation. 

Kim has also indicated he wants to end the country’s nuclear weapons programme during Donald Trump’s first term in the White House – his first indication of a timeline since his historic meeting with the US President in June.

The meeting with South Korean President Moon Jae-in will take place in Pyongyang on September 18-20, Moon’s national security adviser, Chung Eui-yong, said on Thursday after meeting Kim a day earlier.

The two countries plan to open an inter-Korean liaison office before the summit in the North’s border city of Kaesong, staffed by officials from both sides to facilitate consultation, Chung said.

Despite the announcement, the optimism that surrounded the leaders’ first meeting in April – the first time a member of Kim’s dynasty had set foot on southern soil since the end of the Korean War in 1953 – appears to have waned. The leaders were also pictured hugging during a second meeting in May. 

On Sunday, North Korean state media lashed out at the south’s capital Seoul, accusing it of foot-dragging over the Panmunjom agreement – a deal signed by Kim and Moon in April, pledging to end the Korean war and work towards a nuclear-free Peninsula and a new era of peace. It also accused the south of “blind obedience” to US-led sanctions. 

“It’s been more than 100 days since the April 27 Panmunjom Declaration was adopted, but no fruit or progress has been produced. It is because of America’s sanctions and the South’s unfair participation in them,” it said through the state-run Uriminzokkiri website.

The next meeting between the north and south, its hoped, could reinvigorate denuclearisation talks between North Korea and the US, which stalled last month when Trump cancelled a visit to the North by his secretary of state Mike Pompeo, citing a lack of progress. 

Kim told South Korean officials his faith in Trump was “unchanged” and he wanted denuclearisation and an end to hostile relations with the US by 2021 – the end of the president’s first term – Chung said.  

“He (Kim) particularly emphasised that he has never said anything negative about President Trump,” he added. 

North Korea has said in previous, failed talks over the years that it could consider giving up its nuclear programme if the US provided security guarantees by removing its troops from South Korea and withdrawing its so-called nuclear umbrella of deterrence from South Korea and Japan.

US officials involved in negotiations have said North Korea has refused to even start discussions about defining “denuclearisation” or other key terms such as “verifiable” and “irreversible”, and have insisted America must first agree to take simultaneous steps to reduce economic pressure.

Chung said Kim had stressed the need for the US to reciprocate North Korea’s initial moves, which have included dismantling a nuclear test site and a missile engine facility.

The US Embassy in Seoul on Thursday said it had no information to share on the matter.

North Korea’s official KCNA news agency said Kim told Chung and other envoys that it was his “fixed stand” to turn the Korean peninsula into “the cradle of peace without nuclear weapons and free from nuclear threat”.

Chung said Kim showed “frustration over the doubt raised by some parts of the international community about his willingness to denuclearise, and asked us to convey his message to the United States”.

North Korea and the US are at odds over whether denuclearisation or declaring an end to the 1950-53 Korean War should come first.

The war ended with an armistice, not a peace treaty, meaning US-led UN forces, including South Korea, are technically still at war with the North.

North Korea has long sought a formal end to the war but US officials have said an end-of-war declaration could weaken North Korea’s incentive for denuclearisation, and raise questions about the 28,500 US troops stationed in South Korea – a legacy of the three-year conflict

US officials also say they have already made concessions, such as halting joint military exercises with South Korea.