North Korean leader Kim Jong-Il's death at the age of 69 has plunged his country into uncertainty.
Here are key dates in the history of a troubled and secretive nation which has been embroiled in rows with its neighbour South Korea and with world powers over its nuclear ambitions.
1945: Japan's colonial rule over Korea ends with its World War II surrender. Korea is divided at the 38th parallel between the North, backed by the Soviet Union, and the South, supported by the United States.
1950-53: After Soviet and US troops leave the Korean peninsula, the North invades the South and war breaks out. The US intervenes on behalf of the South as part of a United Nations force, and China on the side of the North.
The war leaves an estimated four million dead. The US retains a major military presence in the South.
1988: The US imposes sanctions on North Korea after putting the country on its list of nations supporting terrorism.
1989: US satellite pictures reveal a nuclear reprocessing plant at the Yongbyon complex.
1994: The US comes close to war with North Korea over its removal of spent fuel rods from the Yongbyon reactor. Ex-president Jimmy Carter defuses the crisis with a visit to Pyongyang, which vows to freeze and dismantle its nuclear programme in return for energy aid.
1998: North Korea fires first long-range ballistic missile.
2002: US President George W. Bush names North Korea as part of an "Axis of Evil".
The 1994 accord breaks down after US accusations that the North has a secret nuclear weapons programme using enriched uranium.
2003: North Korea withdraws from the Nuclear Non-Proliferation Treaty. Six-way nuclear talks start in Beijing in August.
2005: For the first time, North Korea states that it has nuclear weapons.
2006: North Korea carries out its first nuclear test on October 9, sparking international condemnation and more UN sanctions.
2007: North Korea agrees in February to scrap its nuclear facilities in return for economic aid and diplomatic benefits. In July, North Korea says it has closed down its main nuclear site.
2008: In June, North Korea blows up the cooling tower at Yongbyon to show its commitment to nuclear disarmament.
In October, Washington removes North Korea from its terrorism blacklist.
2009: April 5: The North launches a long-range rocket and announces it will quit the six-party talks and restart its Yongbyon complex after UN condemnation.
May 25: North conducts its second nuclear test, sparking tougher UN sanctions.
2010: March 26: Forty-six sailors die when a South Korean warship sinks near the North Korean border. International investigators later say it was sunk by a North Korean torpedo, an accusation the North denied.
November 12: North Korea unveils uranium enrichment plant to visiting US scientists. Experts say it could be reconfigured to make atomic weapons.
November 23: North fires shells at a South Korean island, killing four.
2011: July 22: North and South Korean nuclear envoys meet in Bali to discuss possible resumption of six-party talks.
October 24-25: US and North hold a second bilateral meeting, in Geneva, but make no breakthrough.
December 19: North Korean state media say Kim Jong-Il died two days previously of a heart attack at the age of 69, and urge people to support his son and heir apparent Kim Jong-Un. A funeral is scheduled for December 28.
-- South Korea places all troops on emergency alert, Japan calls an emergency security meeting and the US says it is "closely monitoring events".