North Korea said on Tuesday it would quit international nuclear disarmament talks and restart a plant that makes bomb-grade plutonium after the United Nations chastised it for launching a long-range rocket.

The following are milestones in the often-delayed nuclear talks among the two Koreas, China, Japan, Russia and the United States held in Beijing.

* FIRST ROUND - Aug, 2003:

- Tense talks are held in a secluded state guesthouse. North Korea proposes a non-aggression treaty but also threatens to test nuclear weapons and a new missile.

- October 2003 - North Korea says has reprocessed thousands of nuclear fuel rods and increased its fissile material.

* SECOND ROUND - Feb, 2004:

- The second round of talks takes six months of shuttle diplomacy to organize, and makes little progress. Two stumbling blocks cited are North Korea's offer to give up its military nuclear program but retain those for peaceful purposes and its repeated denial that it has an uranium-enrichment program.

* THIRD ROUND - June, 2004:

- The United States offers fuel aid and security guarantees if North Korea scraps its nuclear programs. It is the first detailed proposal since President George W. Bush took office and branded the North part of an axis of evil. Pyongyang says it would freeze plutonium-based nuclear facilities, but refuses to say if it has an uranium-enrichment program.

- February 10, 2005 - North Korea declares itself a nuclear weapons power and says it is quitting the six-country talks.

* FOURTH ROUND - July-Sept, 2005

- A long-awaited joint statement is issued on September 19, after a marathon round goes to recess. In it, North Korea promises to give up its nuclear weapons program in return for energy assistance, security guarantees and greater diplomatic recognition. The agreement says it could have a nuclear energy program in the future if it meets strict safeguards.

- September 20 - North Korea says it will not give up its nuclear weapons program until the United States provides it with civilian atomic reactors. The statement significantly undermines the deal reached the previous day.

* FIFTH ROUND - Nov, 2005:

- Proposals are put forward on how to implement the fourth round's joint statement. Talks break off after Washington says Pyongyang's offer to freeze but not dismantle its nuclear programs in return for compensation is unacceptable.

- April 24, 2006 - North Korea says it will not resume talks unless the United States releases some $24 million of its assets frozen in a Macau bank. Washington suspects funds are linked to illicit activities including money-laundering and drug-running.

July 5 - North Korea launches seven missiles, including its long-range Taepodong-2, which explodes less than a minute into flight.

- October 9 - North Korea carries out first nuclear test.

* SIXTH ROUND - July 2008:

- Envoys seek ways to verify claims North Korea made in nuclear inventory presented in June 2008.

- September 2008 - North Korea, angry about not being removed from U.S. terrorism blacklist, removes IAEA seals on nuclear plant and says will resume its operations.

- October - U.S. nuclear envoy goes to Pyongyang to make last-gasp bid to save nuclear talks.

- December - last session of six-way talks held with almost no progress made.

- April 14, 2009 - North Korea says it is boycotting talks and restarting Yongbyon nuclear plant.