North Korean leader Kim Jong Un has agreed to permanently dismantle his main nuclear complex at Nyongbyon if the United States takes corresponding measures, South Korean president Moon Jae-in said.

It comes after the two leaders held summit talks in Pyongyang to try to sustain nuclear diplomacy with Washington, which has been pushing hard for stronger disarmament moves from the North.

The Korean leaders also said the North would dismantle a missile engine test site and launch pad in the presence of outside inspectors, and would seek to host the 2032 Summer Olympics together.

Mr Moon also said Mr Kim would try to visit Seoul sometime this year.

Koreas Summit
Moon Jae-in and Kim Jong Un pose after signing documents in Pyongyang (Korea Broadcasting System via AP)

Washington wants North Korea to outline the entirety of its nuclear programme, and its response to Wednesday’s joint statement from the Koreas remains to be seen.

While the declaration appears to fall short of what Washington wants, President Donald Trump has maintained that he and Mr Kim have a solid relationship and both leaders have expressed interest in meeting again after their June summit in Singapore.

But Mr Trump’s late-night tweets did not address the US matching North Korea’s moves.

“Kim Jong Un has agreed to allow Nuclear inspections, subject to final negotiations, and to permanently dismantle a test site and launch pad in the presence of international experts. In the meantime there will be no Rocket or Nuclear testing,” Mr Trump said in a pair of tweets.

“Hero remains to continue being returned home to the United States. Also, North and South Korea will file a joint bid to host the 2032 Olympics. Very exciting!”

North Korea has been demanding a declaration formally ending the Korean War, which was stopped in 1953 by a ceasefire, but neither leader mentioned it as they read the joint statement.

“We have agreed to make the Korean Peninsula a land of peace that is free from nuclear weapons and nuclear threat,” Mr Kim said as he stood by Mr Moon’s side at the guesthouse where Mr Moon is staying.

“The road to our future will not always be smooth and we may face challenges and trials we can’t anticipate. But we aren’t afraid of headwinds because our strength will grow as we overcome each trial based on the strength of our nation.”

Mr Kim and Mr Moon earlier smiled and chatting as they walked down a hallway and into a meeting room to finalise the joint statement, which also said that the leaders would push for a Korean peninsula without nuclear weapons and to “eliminate all the danger of war”.

North Korea was expected to hold a huge mass games spectacle later in the day, with Mr Moon attending an event expected to draw about 150,000 spectators, Seoul said. It was not clear if Mr Kim would attend.

North Korea first staged its mass games in 2002, when Mr Kim’s father, Kim Jong Il, was leader. They continued most every year until 2014, then were revived during North Korea’s celebrations of the 70th anniversary of its state founding earlier this month.

South Korea Koreas Summit
Moon Jae-in shakes hands with Kim Jong Un after a joint press conference in Pyongyang, (Lee Jin-man/AP)

Mr Kim gave the South Korean president an exceedingly warm welcome on Tuesday, the first day of the summit, meeting him and his wife at Pyongyang’s airport — itself a very unusual gesture — then riding into town with Mr Moon in an open limousine through streets lined with crowds of North Koreans, who cheered and waved the flag of their country and a blue-and-white flag that symbolises Korean unity.

The made-for-television welcome has become routine for their summits, after two meetings earlier this year.

The summit talks began at the ruling Workers’ Party headquarters where Mr Kim and Mr Moon were joined by two of their top deputies — spy chief Suh Hoon and presidential security director Chung Eui-yong for Mr Moon, and for Mr Kim, his sister, Kim Yo Jong, and senior Workers’ Party official Kim Yong Chol, according to Mr Moon’s office.

At the start of their meeting on Tuesday, Mr Kim thanked Mr Moon for brokering the June summit with Mr Trump.

“It’s not too much to say that it’s Moon’s efforts that arranged a historic North Korea-US summit. Because of that, the regional political situation has been stabilised and more progress on North Korea-US ties is expected,” Mr Kim said, according to South Korean media pool reports and Mr Moon’s office.

Mr Moon responded by expressing his own thanks to Mr Kim for making a “bold decision” in a New Year’s speech to open a new era of detente and send a delegation to the South Korean Winter Olympics in February.