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