A period of national mourning has been declared in North Korea following the death of the country's leader, Kim Jong-il.
The state news agency reports the 69-year-old died of a heart attack on a train on Saturday.
Kim Jong-il has been the leader of the impoverished communist country since the death of his father Kim Il-sung in 1994, the BBC reports.
In 2008, he suffered a stoke and was absent from public view for several months.
Pyongyang described Mr Kim's third son, Kim Jong-un, as the "great successor" and urged North Koreans to unite behind him.
Kim Jong-un, thought to be in his late 20s, was named as his father's successor just over a year ago.
A funeral for Kim Jong-il will be held in Pyongyang on 28 December and Kim Jong-un will head the funeral committee, it reported.
Emergency meetings in Asia
South Korea and Japan have called special security meetings to discuss how Kim Jong-il's death will affect the region.
Uncertainty about the future of North Korea and its nuclear weapons programme has unsettled neighbouring countries.
South Korea's armed forces have been put on alert and a Foreign Ministry official says the country is prepared to deal with all eventualities.
The Japanese government says it hopes the death will not negatively impact on peace and stability on the Korean peninsula.
North Korea's main ally, China, says it was "distressed" to learn of Kim Jong-il's death, but remains confident the North would remain united and the two neighbours would keep up their cooperation.
In the United States, the White House says President Barack Obama has been told about the death and the government is monitoring reports, as well as talking with allies in South Korea and Japan.
New Zealand Prime Minister John Key says he believes there will be some concerns about what Mr Kim's death means for the future of North Korea. However, he hopes for a smooth transition and a better outlook for its people.
Australia's Foreign Minister Kevin Rudd says it is difficult to know what will happen in the days ahead, but urged all parties to stay calm.
Mr Rudd says the death of Kim Jong-il provides the regime with an important opportunity to engage with the international community on how to feed its people, open its economy and deal with its nuclear weapons programme.