December 1985

Pyongyang joins Treaty on the Non-Proliferation of Nuclear Weapons

February 1993

International Atomic Energy Agency demands to inspect suspected nuclear waste sites

June 1994

Withdraws from IAEA

August 1998

Launches three-stage rocket Taepodong 1 over Japan

January 2003

Withdraws from non-proliferation treaty

February 2005

Announces that country has produced nuclear weapons

July 2006

Test-fires ballistic missiles

Oct 9, 2006

Conducts first underground nuclear test

February 2007

Agrees to scrap nuclear facilities in return for aid

April 2009

Launches three-stage Unha 2 rocket

May 25, 2009

Conducts second underground nuclear test

November 2010

Reveals uranium enrichment facility to foreign experts

December 2012

Successfully launches Unha 3, including placement of satellite into orbit

Feb 12, 2013

Conducts third underground nuclear test

September 2015

Restarts Yongbyon reactor

Jan 6, 2016

Pyongyang says it has tested a hydrogen bomb

AFP - China Daily