Nuclear-armed North Korea's dictator Kim Jong Il has died of a heart attack, the reclusive nation's state media announced Monday. He was 69.
Kim, believed to have suffered a stroke in 2008, died on Saturday while travelling by train on one of his field tours, the official KCNA news agency reported.
Kim "passed away from a great mental and physical strain" at 8:30 am local time on Saturday during a "high intensity field inspection," according to the KCNA and state television reports.
An autopsy was done on Sunday and "fully confirmed" the diagnosis.
KCNA signaled that Kim's little-known son Kim Jong Un will be the next leader, calling him a "great successor" to the country's guiding principle of self reliance, or juche.
State television asked all ruling party members, military personnel, and the people to faithfully "follow the leadership of comrade Kim Jong Un and "protect and further strengthen unity."
State media appear to be developing the same personality cult for the potential dynastic successor that surrounded the senior Kim and his father.
The junior Kim, in his 20's, was appointed to senior political and military posts last year in a succession move and was taken on various countrywide tours by his father.
The senior Kim, who is said to have had a taste for cigars, cognac, and gourmet cuisine, had been in power since 1994 when his father died of a heart attack at the age of 82.
Despite the stroke, Kim had travelled recently to his closest ally China and to Russia, and had made numerous trips around the country.
China, which hosts thousands of North Korean refugees fleeing food shortages and human rights abuses in their country, offered its "deep condolences" on Kim's death.
"We are shocked to learn that DPRK top leader comrade Kim Jong Il passed away and we hereby express our deep condolences on his demise and send sincere regards to the DPRK people," Chinese foreign ministry spokesman Liu Weimin said, according to Beijing's state Xinhua news agency.
Kim's funeral will be held in Pyongyang on Dec. 28 but no foreign delegations will be invited, KCNA said, adding that a period of national mourning will be observed up to Dec. 29.
KCNA, quoting a statement from the national funeral committee headed by Kim Jong Un, said the senior Kim's body would lie in state in Kumsusan palace where his father's embalmed body is on display.
Traffic in the North Korean capital was moving as usual Monday, but people in the streets were in tears as they learned the news of Kim's death, according to the Associated Press, which announced earlier this year the opening of its office in Pyongyang, the first permanent text and photo bureau operated by a Western news organization in the North Korean capital.
A foreigner contacted at Pyongyang's Koryo Hotel said hotel staff were in tears, AP reported.
Asian stock markets meanwhile fell on news of Kim's death, which also raised security concerns on the divided Korean peninsula and in the region, where tensions have been running high over Pyongyang's nuclear ambitions.
Kim had ruled the country with an iron hand and had refused to dismantle its illicit nuclear weapons despite persistent international pressure.
Last year, North Korea's military launched a deadly artillery attack on its southern neighbor. The two have remained technically at war since their three-year conflict ended only in an armistice in 1953.
On Monday, South Korea placed its troops and police force on emergency alert, and summoned a meeting of the National Security Council, Agence France-Presse reported.
U.S. President Barack Obama called his South Korean counterpart Lee Myung-Bak of South Korea at midnight on the U.S. East Coast, the White House said in a statement.
"The President reaffirmed the United States' strong commitment to the stability of the Korean peninsula and the security of our close ally, the Republic of Korea," the statement said.
"The two leaders agreed to stay in close touch as the situation develops and agreed they would direct their national security teams to continue close coordination," it added.
U.S. envoy Robert King had held talks in Beijing last week about the possible resumption of U.S. food aid to North Korea amid speculation about separate discussions on reviving six-party talks aimed at ending Pyongyang's nuclear weapons drive.
"We remain committed to stability on the Korean peninsula, and to the freedom and security of our allies," White House press secretary Jay Carney said in a statement Monday.
The United States, which stations 28,500 troops in South Korea, is also in close touch with its other key ally Japan, which has no diplomatic ties with North Korea.
The Japanese authorities called an emergency security meeting as well.
Defence Minister Yasuo Ichikawa said no unusual military moves by the unpredictable regime had been detected, according to AFP.
"I have told [military chiefs] to gather information and to be thorough about surveillance," he said after meeting top brass.
Reported by RFA's Korean service. Written in English with additional reporting by Parameswaran Ponnudurai.