North Korea says it no longer needs to test long-range missiles or nuclear weapons.
But Japanese Defense Minister Itsunori Onodera said he was not satisfied with the announcement, and demanded pressure be kept up on North Korea until it abandons its missile programme in a complete, irreversible and verifiable way.
North Korea has made similar overtures and symbolic gestures ahead of the summit, including reestablishing a dedicated hotline between South Korean President Moon Jae-in and Kim, and agreeing to meet with US President Donald Trump for separate discussions at a later date.
North Korea has announced that it plans to stop conducting nuclear and missile tests, according to the country's state-run news media. Trump welcomed the statement and said he looked forward to a summit with Kim.
Presidential official Yoon Young-chan said in a statement Saturday the announcement will brighten the prospects for successful talks between Seoul, Pyongyang and Washington.
'All they are talking about is the end of hostile policies against North Korea, followed by a guarantee of security'. Last month Kim told a South Korean delegation he "understood" the need for joint US-South Korean military drills.
On Thursday, the South's president revealed that Kim had expressed his commitment to "complete denuclearization" of the Korean peninsula without seeking conditions.
A North Korea source told CNN that Kim has finally chose to open up a new chapter for his nation. He is finally being recognized by the worldwide community, and this is a historic, timely opportunity, the source said. "We would like to keep a close eye on it".
Beijing welcomed the news and pledged to play a "positive" role in bringing lasting peace to the peninsula.
North Korea's decision came amid a peace mood set up on the Korean Peninsula before the two Koreas are set to hold a summit on the southern side of the truce village of Panmunjom on Friday.
Analysts cautioned that the declaration was promising but limited. But South Korea's hosting of the Winter Olympics in February gave an unexpected window for diplomacy, and in the weeks since there have been a flurry of visits to the North from China, South Korea and now the US.
According to the decisions, the DPRK will never use nuclear weapons nor transfer nuclear weapons or nuclear technology under any circumstances unless there are nuclear threats and nuclear provocations against the DPRK. "It would be a great day for them, it would be a great day for the world". It published a six-point list that emphasized the country had achieved its nuclear objectives.
Within minutes of the report being issued, Trump tweeted: "This is very good news for North Korea and the World - big progress!" The explosion created a magnitude 6.3 tremor, making it the most powerful weapon Pyongyang has ever tested.
Lassina Zerbo, executive secretary of the Comprehensive Nuclear-Test-Ban Treaty Organization, described North Korea's annoucement as "a strong signal and an important step in the right direction".
Last year, Pyongyang tested a new intercontinental ballistic missile it said could reach the USA mainland, raising the prospect that Kim could follow through on his threat to target the United States.
This Saturday, the unilateral decision was made public during the extraordinary plenary meeting of the Central Committee of the Workers' Party of Korea, Kim Jong-Un recalled to party leaders that at the end of 2017 this country completed its nuclear program and since then to this date the global situation had changed in a favorable way to the country.
In the announcement, North Korea's leader says he now wants to focus on the country's economy.
Kim Jong Un, the top leader of DPRK, attended the meeting where the decisions were made.