- Video report by ITV News Correspondent Mark McQuillan
North Korea has suspended nuclear and long-range missile tests and plans to close its nuclear test site.
The North's official Korean Central News Agency said the suspension of nuclear and ICBM tests went into effect on Saturday.
The country says it is making the move to shift its national focus and improve its economy.
The announcements came days before North Korean leader Kim Jong Un is set to meet South Korean President Moon Jae-in in a border truce village for a rare summit aimed at resolving the nuclear stand-off with Pyongyang.
President Trump wrote "a message from Kim Jong Un" on Twitter, where he confirmed the announcement, adding: "progress being made for all!"
The North's decisions were made in a meeting of the ruling party's full Central Committee which had convened to discuss a "new stage" of policies.
US president Donald Trump welcomed the announcement, calling it "big progress".
He tweeted: "North Korea has agreed to suspend all Nuclear Tests and close up a major test site.
"This is very good news for North Korea and the World - big progress! Look forward to our summit."
The Foreign Office has described the announcement that North Korea will suspend nuclear tests and intercontinental ballistic missile launches as "a positive step".
A Foreign Office spokeswoman said: "A long term commitment from Kim Jung Un to halt all nuclear tests and ICBM launches would be a positive step. We hope this indicates an effort to negotiate in good faith.
"We remain committed to working with our international partners to bring about our goal of a complete, verifiable and irreversible de-nuclearisation of the Korean peninsula, and to do so through peaceful means."
South Korea's presidential office also welcomed North Korea's announcement as "meaningful progress" toward the denuclearisation of the Korean Peninsula.
Presidential official Yoon Young-chan said in a statement the announcement will brighten the prospects for successful talks between Seoul, Pyongyang and Washington.