North Korea has worked on its nuclear weapons program for decades, seeking to develop a capability that would deter an attack by the United States. With the help of the Soviet Union, North Korea began work on a nuclear program, insisting it was for peaceful purposes. In 1985, North Korea joined the Nuclear Non-Proliferation Treaty (NPT). In 1991, South and North Korea signed an agreement committing both countries to refrain from producing or using nuclear weapons.
North Korea’s tone changed soon after. In 1993, they threatened to quit the NPT after International Atomic Energy Agency officials accused the North of violating the Treaty and demanded access to nuclear waste storage site for inspectors. Then-U.S. President Bill Clinton decided to enter into negotiations with the North, resulting in the 1994 Agreed Framework under which North Korea agreed to freeze and eventually dismantle its nuclear facilities in exchange for normalization of relations with the U.S. among other incentives.
In 2002, the Agreed Framework collapsed with the U.S. accusing North Korea of secretly enriching uranium and halting fuel oil shipments to the North agreed to under the Framework. North Korea formally withdrew from the NPT in 2003. Attempts to re-engage the North on their nuclear program through the Six-Party Talks — a forum that included China, Japan, Russia, South Korea and the U.S. — cycled through moderate successes and complete breakdowns. With this cycle as the backdrop, North Korea began testing long-range ballistic missiles and conducting nuclear tests. In response, the United Nations imposed numerous economic and commercial sanctions.
Fast forward to 2017: North Korea ramped up its missile testing, conducting successful tests of intercontinental ballistic missiles capable of reaching the United States, and completed its sixth nuclear test. U.S. President Donald Trump responded to these provocations with inflammatory tweets, increased military pressure, and threats of “fire and fury like the world has never seen.”
The two leaders volleyed threats back and forth until the 2018 Winter Olympics in South Korea ushered in a period of diplomacy and optimism. South Korean President Moon Jae-in invited North Korea to participate with the South in the opening ceremony, an offer North Korean leader Kim Jong-un accepted. By the closing ceremony, North Korea had signalled its willingness to meet with the U.S.
On June 12, 2018, Trump met with Kim Jong-un in Singapore — the first meeting between a sitting U.S. president and a North Korean leader. The joint declaration issued at the meeting’s conclusion committed both countries to work toward peace in Northeast Asia, including the “complete denuclearization of the Korean Peninsula.”
The next day, Trump declared “there is no longer a nuclear threat from North Korea.” He later claimed, “We will immediately begin total denuclearization of North Korea.” While continued engagement between the two countries is a positive sign, the nuclear threat from North Korea is far from eliminated and a large gap still exists over what denuclearization actually means.
Negotiating the peaceful resolution of the Korean peninsula crisis is not something that happens overnight. Diplomacy is difficult and takes time. Both North Korea and the United States, along with its allies, must continue engagement, working to make real progress and advocate for real steps toward the denuclearization of the Korean peninsula. Only a sustained diplomatic process can reduce the risks of catastrophic and potentially nuclear military confrontation.
It is essential for the U.S. and North Korea to keep moving forward and refrain from returning to the nuclear saber-rattling, escalatory rhetoric and threats of military action that defined relations just last year. And it is essential for us to make sure they do.
Days since the Singapore Summit: 952
Last updated: January 19, 2021
What’s happened since the Singapore Summit:
June 18: U.S. and South Korea announce suspension of August Ulchi Freedom Guardian joint military exercise.
June 21: Commercial satellite imagery suggests improvements to North Korea’s Yongbyon Nuclear Scientific Research Center.
June 29: A report shows U.S. intelligence agencies believe North Korea has increased production of enriched uranium for nuclear weapons at multiple secret sites.
July 6: U.S. Secretary of State Mike Pompeo arrives in Pyongyang, North Korea for talks. Pompeo states he is “seeking to fill in some details on these commitments and continue the momentum toward implementation of what the two leaders promised each other and the world.”
The two countries establish working groups to tackle details, including verification efforts for denuclearization, according to the U.S. State Department.
July 7: North Korea calls talks with the U.S. “deeply regrettable,” citing “demand for denuclearization.” Pompeo says talks were “productive.”
July 12: The U.S. asks the UN Security Council to order a halt to all deliveries of refined oil products to North Korea, citing NK violations.
Trump tweets out a July 6 letter from Kim claiming progress is being made. The letter says nothing about North Korea’s nuclear weapons program.
July 22: The U.S. and North Korea agree to restart field operations to search for the missing remains of thousands of Americans. U.S. officials say the North pledged to return 55 sets of remains on July 27.
July 23: CNN reports, citing an unnamed official, North Korea wants the United States to agree to a legally-binding peace treaty that would ensure the survival of Kim Jong-un’s regime before denuclearization talks can proceed further.
July 25: In a U.S. Senate Foreign Relations Committee hearing, Secretary of State Mike Pompeo says the North Koreans understand the U.S. definition of denuclearization and sanctions will continue to be enforced until “denuclearization as we have defined it is complete.”
July 27: A U.S. Air Force plane carrying the remains of American soldiers who fought in the Korean War arrives at Osan Air Force Base in South Korea.
July 30: The Washington Post reports that U.S. intelligence agencies have evidence that North Korea continues to build new ICBMs.
August 3: A UN Security Council-commissioned report is released saying that North Korea has not stopped its nuclear and missile programs and is trying to sell weapons abroad.
Secretary of State Mike Pompeo states in an interview with Channel NewsAsia that North Korea will decide the timeline for its denuclearization.
August 4: Ri Yong-ho, North Korea’s foreign minister, says at a regional security forum in Singapore that the U.S. is not taking actions reciprocal to those taken by North Korea in its move toward denuclearization.
August 7: National security advisor John Bolton states in an interview on Fox News that North Korea has not taken any steps to denuclearize.
August 13: North and South Korea release a joint statement saying the two countries plan to hold a summit meeting.
August 15: South Korean President Moon Jae-in proposes a plan for broader economic cooperation with North Korea.
August 20: Korean families separated during the Korean War are allowed to meet at a resort in southeast North Korea.
President Trump says in an interview with Reuters that he would most likely meet with Kim Jong-un again.
The IAEA releases a report saying that North Korea has not curtailed its nuclear program.
August 21: The U.S. releases new sanctions targeting Russian companies doing business with North Korea.
The South Korean Minister of Defence announces that North and South Korea have agreed to shut down some guard posts between the two countries.
August 22: South Korea announces that it is moving ahead with plans to open a diplomatic liaison office in the North.
August 24: President Trump cancels Secretary of State Mike Pompeo’s trip to North Korea, citing lack of progress toward denuclearization.
South Korea releases customs data showing it sent nearly US$1 million of sanctioned materials to North Korea over the previous two months.
August 28: Secretary of Defense James Mattis announces that the U.S. has no plans to suspend any more joint military drills with South Korea.
August 29: President Trump tweets accusations that China is undermining U.S. negotiations with North Korea.
August 30: The U.S.-led U.N. command denies an application for a rail project linking North and South Korea.
The U.S. State Department announces that it is extending a ban on U.S. citizens travelling to North Korea for another year.
September 6: The U.S. Department of Justice accuses North Korea of conducting a years-long hacking campaign against American companies and international financial institutions.
September 7: U.S. and North Korean generals meet to discuss the possibility of recovering more remains of American soldiers killed during the Korean War.
September 9: North Korea holds its annual military parade, but does not include its ICBMs.
September 19: Kim Jong-un tells Moon Jae-in that he will commit to dismantling nuclear fuel production facilities.
September 24: CIA Director Gina Haspel expresses skepticism that North Korea will give up its nuclear weapons.
September 29: Ri Yong-ho, North Korea’s Foreign Minister, says in a speech at the U.N. general assembly that there was no way North Korea would denuclearize without trust-building concessions from the U.S.
October 4: The U.S. imposes sanctions on a Turkish company and individuals for doing business with North Korea.
October 10: President Trump states that the South Korean government wouldn’t lift an embargo on the North without U.S. approval.
November 2: North Korea threatens to resume its nuclear program unless the U.S. grants it relief from sanctions.
November 5: The U.S. and South Korea resume joint military drills.
November 7: the U.S. State Department announces that a meeting with North Korea has been cancelled.
November 12: The Center for Strategic and International Studies releases a report indicating that North Korea is moving forward with its ballistic missile program.
November 16: North Korea announces that it has tested a new tactical weapon.
November 20: Secretary of State Mike Pompeo says in a press conference that North Korea’s denuclearization should not lag behind the development of stronger North-South relations.
North Korea blows up the first of ten DMZ guard posts, per an agreement with the South.
November 24: the U.N. Security Council grants an exemption to North Korea sanctions for an exploratory study on a rail link between the two countries.
November 27: North Korean Ambassador to the U.N. Kim Song sends letters to the members of the U.N. Security Council accusing the U.S. of stoking confrontation by calling for a meeting on human rights in North Korea.
December 4: National security advisor John Bolton says that North Korea’s failure to fulfill its commitments requires another summit meeting.
December 7: North Korean Foreign Minister Ri Yong-ho says in a meeting with his Chinese counterpart Wang Yi that North Korea was committed to ending its nuclear weapons program.
December 10: The U.S. imposes new sanctions on three North Korean officials, citing human rights abuses and the death of Otto Warmbier.
December 16: North Korea releases a statement saying new U.S. sanctions could permanently foreclose the possibility of denuclearization.
December 20: North Korea’s Korean Central News Statement releases a statement saying that the North would not give up its nuclear weapons unless the U.S. removed the nuclear threat.
December 24: A Washington, D.C. federal judge orders North Korea to pay over $500 million to the parents of Otto Warmbier.
December 26: North and South Korea hold a ground-breaking ceremony for a rail link between the two countries.
December 31: Kim Jong-un sends a letter to Moon Jae-in stating that the North Korean leader would like to visit South Korea.
January 1: During his annual New Year’s speech, Kim Jong-un states that he is ready to meet with President Trump again.
January 4: An editorial in the North Korean newspaper Rodong Sinmun warns the U.S. to stop meddling in the North Korea-South Korea relationship.
January 17: The U.S. Missile Defense Review identifies North Korea as an “extraordinary threat.”
January 21: The Center for Strategic and International Studies releases a report identifying an undeclared missile site.
February 12: General Robert Abrams, Commander of U.S. Forces Korea, says that there has been “little to no verifiable change” in North Korean military capabilities.
February 24: Secretary of State Mike Pompeo states that North Korea remains a threat to the United States, contradicting statements by President Trump.
February 26: The Trump-Kim summit meeting begins in Hanoi.
February 28: The Trump-Kim summit ends early without a deal.
March 1: U.S. officials say that the U.S. and South Korea will terminate their annual Key Resolve and Foal Eagle military drills, opting to conduct smaller-scale drills instead.
March 3: National Security Advisor John Bolton defends President Trump’s conduct at the Hanoi Summit on Fox News, saying the summit was not a failure.
March 5: South Korea’s National Intelligence Service reports that North Korea is rebuilding its Dongchang-ri missile launch site.
March 15: North Korea threatens to suspend negotiations with the Trump administration and resume nuclear and missile tests.
March 21: The Trump administration imposed sanctions on two Chinese shipping companies believed to be helping North Korea evade existing sanctions.
March 29: A planned April 11 trip for Moon Jae-in to Washington is announced.
March 31: North Korea calls a break-in at its embassy in Madrid a “flagrant violation of international law” and called on the government of Spain to launch a full investigation.
April 4: South Korean National Security advisor Chung Eui-yong announced that South Korea was considering sending a special envoy to the North to restart stalled nuclear talks.
April 18: North Korea test-fires a “tactical guided weapon.”
April 24-26: Putin and Kim Jong Un meet in Vladivostok.
May 4: North Korea test-fires rockets and “tactical guided weapons.”
May 8: U.S. suspends efforts to retrieve war remains from North Korea.
May 9: North Korea test-fires two short-range missiles.
The U.S. announces it seized a North Korean carrier ship that was being used to export North Korean coal, a violation of international sanctions.
May 14: North Korea demands the release of a ship impounded by the U.S. for evading sanctions.
May 24: North Korea says talks with the U.S. will not resume unless the White House moves away from demands for unilateral disarmament.
Trump’s National Security Advisor John Bolton says the North Korean weapons tests violated UN Security Council resolutions and they should return to denuclearization talks.
June 11: Trump tells reporters he received a “beautiful letter” from Kim though nuclear negotiations at a working level need to advance before a third summit between the two.
June 20-21: Chinese President Xi visits Kim in Pyongyang, the first visit of a Chinese leader in 14 years. Analysts see the meeting as an opportunity to move denuclearization talks forward.
June 25: New images appear to confirm North Korea has been building a space environment test center, which could help them create more advanced nuclear warheads.
June 27: North Korea warns the U.S. it will resort to military action if diplomatic relations between Washington and Pyongyang remain unsteady.
June 30: President Trump visits North Korea, the first sitting U.S. president to do so. He and Kim Jong Un met on the North Korean side of the Demilitarized Zone.
July 2: North Korea hurls insults at Japan calling it a “malignant tumor” due to Japan’s recent plans. The Japanese intend to station Aegis Ashore interceptors to prepare for a possible ballistic missile attack launched by North Korea. North Korea exclaimed that Japan is “destroying peace and stability in Northeast Asia.”
July 3: North Korea’s mission to the United Nations accuses the United States in a statement of being “more and more hell-bent on hostile acts.”
July 9: A State Department spokesperson states that a nuclear freeze would be a precondition for, not a goal of, U.S. negotiations with North Korea.
July 11: North Korea criticizes South Korea’s purchase of two F-35A jets and says it will develop “special armaments” to destroy them.
Kim Jong Un is officially named head of state of North Korea via constitutional amendment.
July 15: In an interview on the Sean Hannity Show, Secretary of State Michael Pompeo states that he hoped that North Korea could be “a little more creative” in future negotiations.
July 16: North Korea issues two statements expressing its opposition to upcoming joint US-South Korea exercises.
July 23: North Korean state media releases photos of Kim Jong Un inspecting a new submarine.
July 25: North Korea announces a test of a “‘new-type tactical guided weapon,’” describing the test as a warning to “‘military warmongers’” in South Korea, which is preparing for joint military exercises with the United States.
July 26: President Trump discussed North Korean missile launches during a press briefing: “They’re short-range missiles. And my relationship is very good with Chairman Kim. And we’ll see what happens. But they are short-range missiles, and many people have those missiles.”
July 31: South Korea’s Joint Chiefs of Staff release a statement saying North Korea has tested two more short-range missiles.
August 2: North Korea tests two short-range missiles.
August 3: The North Korean Korean Central News Agency announces that North Korea has tested a new multiple rocket launcher system.
August 6: North Korea launches two short-range ballistic missiles.
North Korea issues a statement objecting to upcoming U.S.-South Korea military exercises, and saying that it would “seek a new road” if South Korea and the U.S. continue to “sharpen a sword to do us harm.” It did not mention the missile launches.
A North Korean diplomat, Ju Yong-chol, tells the Conference on Disarmament that the U.S. and North Korea were “inciting military tension” by planning joint military exercises.
August 10: North Korea launches two short-range ballistic missiles.
President Trump tweets that Kim Jong-un sent him a letter asking to restart negotiations after U.S.-South Korea military exercises were completed and apologizing for recent missile tests.
August 21: U.S. Special Representative for North Korea Steve Biegun tells reporters in Seoul that the U.S. is ready to resume talks with North Korea “as soon as we hear from our counterparts in North Korea.”
August 23: North Korea launches two short-range ballistic missiles.
August 25: Speaking at the G-7 meeting, President Trump says he is “not happy” about North Korea missile tests, though they did not violate any agreement.
September 11: North Korea announces that it had conducted a test of a rocket launcher.
September 20: North Korea’s envoy to talks with the U.S. Kim Myong Gil praises the firing of National Security Advisor John Bolton as “a wise decision.”
October 1: The U.S. State Department confirms that the U.S. and North Korea are set to resume talks the following week.
October 2: North Korea conducts a test of a submarine-launched ballistic missile.
October 5: Negotiations between the U.S. and North Korea in Stockholm break down soon after beginning.
October 7: North Korea calls off negotiations with the U.S., warning that it has one year to change its approach.
A North Korean fishing boat collides with a Japanese vessel in the waters off Japan’s Noto Peninsula.
October 10: The South Korean Navy announces it is considering acquiring nuclear-powered submarines.
October 24: North Korea’s Korean Central News Agency publishes a statement attributed to First Vice Minister of the North Korean Ministry of Foreign Affairs Kim Kye Gwan urging the United States to “act wisely” through the end of the year, referencing a deadline set by Kim Jong Un for the U.S. to propose terms for a deal.
October 27: North Korea’s Korean Central News Agency publishes a statement by senior official Kim Yong Chol expressing frustration with the U.S. approach to negotiations and warning the U.S. to take seriously its end-of-the-year deadline for proposing terms for a deal.
November 1: North Korea reports a test of “super-large multiple rocket launchers” conducted the day before. Similar tests were conducted in August and September.
November 14: North Korean representative to talks with the U.S. Kim Myong Gil rejects a proposal to North Korea to resume talks sent by the U.S. through a third party as “a trick to earn time.”
November 17: The U.S. and South Korea postpone joint air drills.
November 18: First Vice Minister of the North Korean Ministry of Foreign Affairs Kim Kye Gwan rejects the prospect of another “fruitless” one-on-one meeting between President Trump and Kim Jong Un.
November 28: North Korea launches two short-range rockets from its east coast.
December 3: Ri Thae Song, North Korea’s Vice Minister of Foreign Affairs, releases a statement saying, with reference to Kim Jong Un’s end-of-year deadline for the U.S. to propose terms for a new agreement: “What is left to be done now is the U.S. option and it is entirely up to the U.S. what Christmas gift it will select to get.”
December 7: North Korean ambassador to the UN Kim Song says that denuclearization talks with the U.S. were “out of the negotiating table.”
December 8: North Korea announces that it carried out a “very important test” on December 7 at the Sohae Satellite Launching Ground.
North Korean official Kim Yong Chol refers to President Trump as “a heedless and erratic old man[…]bereft of patience,” in reference to his tweets.
President Trump responds to North Korea’s test announcement by threatening that it could lose its “special relationship” with the U.S.
December 9: The U.S. blocks a meeting by the U.N. Security Council on human rights violations in North Korea for the second year in a row.
December 11: U.S. Ambassador to the United Nations Kelly Craft tells a meeting of the U.N. Security Council that the U.S. is prepared to take “simultaneous steps” with North Korea to achieve peace on the Korean Peninsula.
December 13: North Korea conducts a test of an advanced missile engine.
December 16: At a news conference in Seoul, U.S. Special Representative for North Korea Stephen Biegun says that new weapons tests would be most “unhelpful in achieving a lasting peace on the Korean Peninsula.”
December 24: In an end-of-year interview, Chinese Foreign Minister Wang Yi encourages the U.S. and North Korea to work out a plan for “realizing complete denuclearization on the [Korean] Peninsula.”
January 1: During a four-day meeting of the Workers’ Party of Korea, Kim Jong Un says that North Korea is no longer bound by its self-imposed moratorium on nuclear and long-range ballistic missile tests, and threatened “shocking actual action.”
January 22: A senior U.S. State Department official says that efforts to denuclearize the Korean Peninsula will continue despite the appointment of Ri Son Gwon, perceived as a hardliner, as North Korean Foreign Minister.
February 24: South Korea’s foreign minister Kyang Kyung Wha calls for a quick resumption of stalled U.S.-North Korean nuclear talks, and says that South Korea stands ready to facilitate dialogue.
March 2: North Korea successfully launches two short-range missiles during military exercises.
March 9: North Korea fires three projectiles reaching a peak altitude of 50 km before landing in the Sea of Japan.
March 21: South Korea’s Joint Chiefs of Staff announce that North Korea fired two short-range ballistic missiles off the country’s east coast.
March 28: South Korea’s Joint Chiefs of Staff say in a statement that North Korea fired what appeared to be two short-range ballistic missiles into the Sea of Japan.
March 30: North Korea’s Foreign Ministry department director general in charge of negotiations with Washington says in a statement that “‘reckless remarks’ by U.S. Secretary of State Mike Pompeo made it clear that Washington has no intention of resuming nuclear talks, and warned that it is now compelled to pay back ‘the pains the U.S. has imposed on our people.’”
April 14: North Korea launches ground-launched and air-launched missiles into the Sea of Japan.
May 3: North and South Korea exchange fire at the Demilitarized Zone (DMZ). No casualties are reported.
May 26: A UN Command probe fails to establish whether North Korea fired accidentally across the DMZ on May 3, and accused both North and South Korea of violating the 1953 ceasefire.
June 4: North Korean state media releases a statement deeply critical of the United States and South Korea and threatens to break the agreement establishing a liaison office in the DMZ in retaliation for the South’s recent propaganda leafleting campaign.
June 11: In a speech on the second anniversary of the Singapore Summit, North Korean Foreign Minister Ri Son-gwon says the country will increase its nuclear arsenal.
June 12: Head of United Front Department (UFD) Jang Kum Chol says that North Korea would soon take “painful” action against South Korea for failing to stop activist groups from dropping propaganda leaflets in North Korea’s territory.
June 15: North Korean state media announces that the country is considering increasing its military presence in parts of the DMZ.
June 16: North Korea blows up a liaison office used for talks with the South.
July 1: South Korean President Moon Jae-in says during a video conference with European Council president Charles Michel that U.S. President Donald Trump and North Korean leader Kim Jong Un should meet again before the U.S. presidential election in November.
July 4: A statement by North Korea’s Vice Foreign Minister Choe Son Hui says that the North does not “feel any need” to conduct additional negotiations with the United States before the U.S. presidential election in November.
July 8: After speaking with reporters, U.S. Deputy Secretary of State Stephen Biegun tells reporters that the U.S. is ready to resume negotiations with the North.
July 9: Kim Yo Jong releases a statement saying that another U.S.-North Korea summit is unlikely, but that the North does not intend to threaten the U.S.
July 10: Japanese Foreign Minister Toshimitsu Motegi and U.S. Deputy Secretary of State Stephen Biegun affirm that the two countries will collaborate on issues relating to North Korea.
July 28: Kim Jong-un reportedly says in a speech that North Korea’s nuclear weapons guarantee its future security forever.
August 6: The U.S. and South Korea will conduct their annual drills digitally this month, a continuation of the Trump administration’s decision to scale back drills as part of negotiations with the North.
September 3: South Korean ambassador to the U.S. Lee Soo-Hyuck says that North Korea is likely waiting until after the U.S. elections to reopen negotiations with Washington over its nuclear arsenal.
September 15: South Korea’s defense ministry affirms that none of its joint military action plans with the United States include any use of nuclear weapons.
October 10: North Korea unveils new military capabilities, including a new ICBM, at a nighttime military parade.
January 12: At the North Korean Workers’ Party conference, Kim Jong-il calls for strengthening North Korea’s nuclear forces.
January 14: North Korea unveils a new submarine-launched missile.
January 18: South Korean President Moon Jae-in expresses hope for new talks with North Korea during a press conference.
In June 2017, the Nuclear Crisis Group recommended key steps to lower the risk of nuclear use and resolve the crisis on the Korean Peninsula. You can read those recommendations here.