DPRK leader Kim Jong-un signs a document regarding the test of a hydrogen bomb, in this still image taken from KRT video and released by Yonhap on Jan 6, 2016. [Photo/Agencies]

DPRK missile and nuclear timeline

・ 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