WASHINGTON (Reuters) - Here is a look at the Obama administration's outreach to North Korea leading up to the "Leap Day" agreement and Pyongyang's subsequent announcement of an April satellite launch that threatens to tear the deal apart.
January 20, 2009 - U.S. President Barack Obama inaugurated.
February 20, 2009 - U.S. Secretary of State Hillary Clinton names Stephen Bosworth, a veteran U.S. diplomat and former ambassador to South Korea, as U.S. Special Representative for North Korea Policy.
April 5, 2009 - North Korea launches missile carrying a satellite over the Sea of Japan. The test fails to make orbit, but prompts unanimous condemnation by the U.N. Security Council as a violation of sanctions barring the use of ballistic missile technology.
April 14, 2009 - North Korea condemns U.N. Security Council statement, withdraws from the "Six Party Talks" on its nuclear program. Pyongyang demands the withdrawal of International Atomic Energy Agency (IAEA) inspectors and U.S. technical experts monitoring its Yongbyon nuclear site, and announces its intention to reactivate its nuclear facilities.
May 25, 2009 - North Korea announces new test of nuclear explosive device, its first since October 2006.
June 12, 2009 - U.N. Security Council unanimously adopts expanded sanctions on Pyongyang, including a ban on arms transfers to and from North Korea.
July 3-4, 2009 - North Korea fires series of short-range ballistic missiles into the Sea of Japan. Additional missile tests take place in October.
December 8, 2009 - U.S. North Korea envoy Stephen Bosworth begins three-day visit to Pyongyang in first direct high-level contact between North Korea and the Obama administration. Talks are inconclusive.
March 26, 2010 - South Korean warship, the Cheonan, torpedoed in waters near disputed boundary with North, killing 46 sailors. An international team of investigators concludes North Korea is responsible, but Pyongyang denies involvement.
November 20, 2010 - Stanford University nuclear scientist Siegfried Hecker issues report saying North Korea showed him "astonishingly modern" new uranium enrichment facility, indicating Pyongyang now has second route to develop atomic weapons along with its existing plutonium program.
November 23, 2010 - North Korea shells South Korea's Yeonpyeong island, the first such attack on a civilian area on South Korean soil since the end of the 1950-53 Korean war.
March 25, 2011 - The United Nations issues report saying more than 6 million people in North Korea urgently need food aid due to substantial cuts in agricultural output, commercial imports and foreign assistance.
May 24, 2011 - U.S. special envoy for North Korean human rights, Robert King, leads trip to North Korea to assess food shortages. The team, which includes officials from the U.S. Agency for International Development (USAID), concludes that North Korea is suffering from widespread, chronic malnutrition but does not publicize its findings.
July 24, 2011 - U.S. Secretary of State Hillary Clinton announces chief North Korean nuclear negotiator Kim Kye-gwan has been invited to New York to discuss possible "pre-steps" to resuming Six Party Talks.
July 28-29, 2011 - North Korea and the United States hold talks at the U.S. Mission to the United Nations in New York. Bosworth describes talks as "constructive", but says too early to judge whether a return to Six Party talks is possible.
August 1, 2011 - North Korea says it has agreed to further dialogue with the United States on the nuclear issue.
August 9, 2011 - Pentagon announces it has sought talks with Pyongyang about repatriating the remains of American soldiers killed in the Korean War. Pyongyang later accepts the proposal, and the two sides meet in October in Thailand.
August 18, 2011 - The United States announces it has offered up to $900,000 to North Korea in emergency flood assistance.
October 24-25, 2011 - The United States and North Korea hold two days of talks in Geneva on the nuclear issue. Bosworth is succeeded by new U.S. envoy for North Korea, veteran negotiator Glyn Davies. U.S. describes the tone as "positive and generally constructive."
December 15-16, 2011 - U.S. rights envoy King holds two days of talks with North Korea on resuming food aid, stresses that talks on food are not linked to the nuclear issue.
December 18, 2011 - North Korea announces that veteran leader Kim Jong-il has died. State news agency later reports that Kim's son, Kim Jong-un, is "great successor."
December 19, 2011 - U.S. Secretary of State Hillary Clinton urges North Korea's new leaders to "follow the path of peace." U.S. officials say they are in touch with North Korean officials to continue technical discussions on possible food aid.
February 24, 2012 - U.S. envoy Davies meets North Korean negotiator Kim for two days of talks in Beijing, says two sides make limited progress and there is no apparent change in North Korea's position despite leadership transfer.
February 25, 2012 - North Korea threatens to wage "sacred war" against South Korea and the United States in response to planned joint military exercises.
February 29, 2012 - The United States and North Korea announce "Leap Day" deal under which Pyongyang agrees to suspend major elements of its atomic program and the United States pledges to provide 240,000 tonnes of food aid.
March 16, 2012 - North Korea announces plans to launch a satellite to commemorate centenary of birth of its founder, Kim Il-sung. The United States and its allies condemn launch plan as a test of banned ballistic missile technology that could scuttle the "Leap Day" deal.
March 28, 2012 - U.S. announces it has formally suspended plans to provide food aid to North Korea.
Reporting by Andrew Quinn; Editing by Xavier Briand