1985
North Korea joins the Treaty of the non-proliferation of Nuclear Weapons as a non-nuclear weapon state.
1986
They start their operation of a five-megawatt nuclear reactor at Yongbyon after seven years of plan with Soviet help.
1993
They say they will quit the nuclear non-proliferation treaty, but later delays their withdrawal.
1994
They sign an agreement with the US under which the North shuts down the plutonium-based Yongbyon nuclear reactor in exchange for help in building two nuclear reactors for producing electricity.
2002
January 29
The US president, George Bush, labeled North Korea, Iran and Iraq an "axis of evil".
October 4
Washington says North Korea admitted to a visiting US delegation that it has a uranium enrichment program.
November 21
US-led consortium says it is suspending construction of the two new reactors.
2003
January 11
They withdraw from the nuclear non-proliferation treaty.
August 27-29
They join first round of six-nation nuclear talks in Beijing, which include China, Japan, Russia, South Korea and the US.
2005
February 10
They announce they have nuclear weapons.
2006
October 9
They hold an underground nuclear test blast.
2007
February 13
They agree to a six-nation talk to take first steps to disarmament, after the US moves to help free some $25m frozen in North Korean accounts.
July 14
North Korea shuts down its Yongbyon reactor.
September 6
Israeli warplanes bomb a Syrian nuclear reactor site allegedly built with North Korean design help.
October 3
The six countries at nuclear talks agree that North Korea will provide a complete declaration of its nuclear programs and disable facilities at its main reactor complex by December 31.
November 5
They start disabling the Yongbyon reactor under the watch of US experts.
December 31
They miss its deadline for declaring all its nuclear programmes.
2008
February 26
The New York Philharmonic performs in Pyongyang, in the highest-level cultural exchange between the US and North Korea since the 1950-53 Korean War.
April 24
The White House says North Korea assisted Syria's secret nuclear program and that the nuclear reactor destroyed by Israel was not intended for peaceful purposes.
May 8
North Korea gives the US more than 18,000 pages of records on the Yongbyon reactor after discussions between the two countries to resolve disagreements over what its nuclear declaration will include.
May 16
The US announces it will provide North Korea with 50,000 tonnes of food aid as a humanitarian gesture unrelated to the nuclear talks.
June 26
US begins steps to remove North Korea from list of states sponsoring terrorism after Pyongyang submitted inventory of its nuclear activities.
August 26
Pyongyang suspends disablement of nuclear facilities, accusing US of reneging on disarmament agreement.
September 3
South Korea says reconstruction has started at North Korea's Yongbyon complex.
September 24
UN nuclear inspectors expelled from North Korea, which pledges to resume plutonium processing.
October 12
Pyongyang says will resume dismantling nuclear weapons programme after US removes North Korea from list of terrorism-sponsoring states.
November 12
The relationship between North and South Korea get worse with Pyongyang announcing that it will close border crossings in December.
2009
February 24
Speculation mounts that North Korea plans long-range missile tests in defiance of American warnings not to destabilise region.
March 30
US and Japan deploy anti-missile batteries on land and sea to shoot down possible debris from the expected missile test although US insists has no intention of shooting down missile itself.
April 3
Barack Obama warns North Korea cannot go ahead with missile tests with permission.
April 4
Pyongyang launches a long-range rocket over Japan, drawing international disapproval.
