SEOUL (Reuters) - North and South Korea will hold their first summit in more than a decade on April 27, South Korean officials said on Thursday, after North Korean leader Kim Jong Un pledged his commitment to denuclearization as tensions ease between the old foes.

South Korean officials, who announced the date after high-level talks with North Korean counterparts, said the agenda would largely be denuclearization of the Korean peninsula and improving inter-Korean relations.

The two Koreas had agreed to hold the summit at the border truce village of Panmunjom when South Korean President Moon Jae-in sent a delegation to Pyongyang this month to meet North Korean leader Kim Jong Un.

Thursday’s meeting was the first high-level dialogue between the two Koreas since the delegation returned from the North.

The two sides said in a joint statement they would hold a working-level meeting on April 4 to discuss details of the summit, such as staffing support, security and news releases.

“We still have a fair number of issues to resolve on a working level for preparations over the next month,” said Ri Son Gwon, the chairman of North Korea’s committee for the peaceful reunification of the country in closing remarks to the South Korean delegation.

“But if the two sides deeply understand the historic significance and meaning of this summit and give their all, we will be able to solve all problems swiftly and amicably,” Ri added.

Tension over North Korea’s tests of nuclear weapons and ballistic missile surged last year and raised fears of U.S. military action in response to North Korea’s threat to develop a nuclear weapon capable of hitting the United States.

But tension has eased significantly since North Korea decided to send athletes to the Winter Olympics in South Korea in February. The neighbours are technically still at war after the 1950-53 conflict ended with a ceasefire, not a truce.

China commended both sides for their efforts to improve ties.

“We hope the momentum of dialogue can continue and that the peaceful situation also can last,” Chinese foreign ministry spokesman Lu Kang told a briefing.

United Nations Secretary-General Antonio Guterres said he was encouraged by the recent developments with North Korea.

“I believe that in this world where unfortunately so many problems seem not to have a solution, I think there is here an opportunity for a peaceful solution to something that a few months ago was haunting us as the biggest danger we were facing,” Guterres told reporters on Thursday.

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‘RESOLVE PROBLEMS’

Kim is scheduled to meet U.S. President Donald Trump in May to discuss denuclearization, although a time and place have not been set.

Kim met Chinese President Xi Jinping in a surprise visit to Beijing this week, his first trip outside the isolated North since he came to power in 2011.

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Even more surprising was Kim’s pledge to denuclearize the Korean peninsula. That commitment was reported by Chinese state media, although North Korea’s official media made no mention of it, or Kim’s anticipated meeting with Trump.

A senior Chinese official visiting Seoul on Thursday to brief South Korea on Kim’s visit to Beijing said it should help ease tension and lead to the denuclearization of the peninsula.

“We believe his visit will help the denuclearization of the Korean peninsula, ensure peace and security of the Korean peninsula and resolve problems regarding the peninsula through political negotiations and discussions,” Yang Jiechi said in opening remarks during a meeting with South Korea’s National Security Office head, Chung Eui-yong.

Yang, a top Chinese diplomat, is scheduled to meet South Korean President Moon Jae-in on Friday.

South Korean Unification Minister Cho Myong-gyon told reporters Kim’s visit to China was not discussed with North Korean officials in their Thursday talks.

Trump and Kim had exchanged insults and veiled threats of war in recent months but the U.S. leader made the surprising announcement this month that he was prepared to meet Kim to discuss the crisis over the North’s development of weapons.

The North Korean leader’s engagement with the international community has sparked speculation that he may try to meet other leaders. Japan’s Asahi newspaper said Japan had sounded out the North Korean government about a summit.

Japan’s Foreign Minister Taro Kono left open the possibility that Prime Minister Shinzo Abe might meet Kim at some point. Kono said in an interview with Reuters on Tuesday that Japan was closely watching preparations for the North-South Korean summit and the Trump-Kim meeting.

Xi promised that Beijing would uphold its friendship with North Korea after his meeting with Kim.

Trump wrote on Twitter he had received a message from Xi late on Tuesday that his meeting with Kim “went very well” and that Kim looked forward to meeting the U.S. president.