SEOUL, South Korea – Kim Jong Il, North Korea's longtime leader, has died at 69 of a heart attack, state TV reported on Monday in a "special broadcast."
State media reported that Kim suffered the heart attack while riding a train on Dec. 17, and that he had been treated for cardiac and cerebrovascular diseases for some time. It said an autopsy was done on Dec. 18 and "fully confirmed" the diagnosis.
"It is the biggest loss for the party ... and it is our people and nation's biggest sadness," an anchorwoman clad in black Korean traditional dress said in a voice choked with tears. She said the nation must "change our sadness to strength and overcome our difficulties."
Kim is believed to have suffered a stroke in 2008, but he had appeared relatively vigorous in photos and video from recent trips to China and Russia and in numerous trips around the country carefully documented by state media. The communist country's "Dear Leader" -- reputed to have had a taste for cigars, cognac and gourmet cuisine -- was believed to have had diabetes and heart disease.
South Korean media, including Yonhap news agency, said South Korea put its military on "high alert" and President Lee Myung-bak convened a national security council meeting after the news of Kim's death. Officials couldn't immediately confirm the reports.
In September 2010, Kim Jong Il unveiled his third son, the twenty-something Kim Jong Un, as his successor, putting him in high-ranking posts.
State media called Kim Jong Un the "great successor" to the nation's principles Monday, encouraging support for the heir-apparent.
It also said saying citizens must "respectfully revere" Kim Jong Un.
"At the leadership of comrade Kim Jong Un, we have to change sadness to strength and courage and overcome today's difficulties," it said.
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. A foreigner contacted at Pyongyang's Koryo Hotel said hotel staff were in tears.
Asian stock markets moved lower amid the news, which raises the possibility of increased instability on the divided Korean peninsula.
South Korea's Kospi index was down 3.9 percent at 1,767.89 and Japan's Nikkei 225 index fell 0.8 percent to 8,331.00. Hong Kong's Hang Seng slipped 2 percent to 17,929.66 and the Shanghai Composite Index dropped 2 percent to 2,178.75.
Kim ruled North Korea with an iron fist for 17 years. He succeeded his father, revered North Korean founder Kim Il Sung, after the elder Kim's death in 1994. The nation remains one of the last remnants of the Cold War era, and is heavily isolated.
Kim maintained absolute control of his country and kept the world on edge with erratic decisions regarding the country's nuclear weapons program.
North Korean legend has it that Kim was born on Mount Paektu, one of Korea's most cherished sites, in 1942, a birth heralded in the heavens by a pair of rainbows and a brilliant new star. Soviet records, however, indicate he was born in Siberia in 1941.
The elder Kim fought for independence from Korea's colonial ruler, Japan, from a base in Russia for years. He returned to Korea in 1945, emerging as a communist leader and becoming North Korea's first leader in 1948.
He meshed Stalinist ideology with a cult of personality that encompassed him and his son. Their portraits hang in every building in North Korea, and every dutiful North Korean wears a Kim Il Sung lapel pin.
Kim Jong Il, a graduate of Pyongyang's Kim Il Sung University, was 33 when his father anointed him his eventual successor.
Even before he took over, there were signs the younger Kim would maintain -- and perhaps exceed -- his father's hard-line stance.
South Korea has accused Kim of masterminding a 1983 bombing that killed 17 South Korean officials visiting Burma, now known as Myanmar. In 1987, the bombing of a Korean Air flight killed all 115 people on board; a North Korean agent who confessed to planting the device said Kim had ordered the downing of the plane.
When Kim came to power in 1994, he had been groomed for 20 years to become leader. He eventually took the posts of chairman of the National Defense Commission, commander of the Korean People's Army and head of the ruling Worker's Party. His father remained as North Korea's "eternal president."
He continued his father's policy of "military first," devoting much of the country's scarce resources to its troops -- even as his people suffered from a prolonged famine -- and built the world's fifth-largest military.
Kim also sought to build up the country's nuclear arms arsenal, leading to North Korea's first nuclear test, an underground blast conducted in October 2006. Another test came in 2009, prompting U.N. sanctions.
Alarmed, regional leaders negotiated a disarmament-for-aid pact that the North signed in 2007 and began implementing later that year. The process has since stalled, though diplomats are working to restart negotiations.
Following the famine, the number of North Koreans fleeing the country rose dramatically, with many telling tales of hunger, political persecution and rights abuses that North Korean officials emphatically denied.
Kim often blamed the U.S. for his country's troubles and his regime routinely derides Washington-allied South Korea as a puppet of the Western superpower.
Former U.S. President George W. Bush described Kim as a tyrant. "Look, Kim Jong Il is a dangerous person. He's a man who starves his people. He's got huge concentration camps. And ... there is concern about his capacity to deliver a nuclear weapon," Bush said in 2005.
Defectors from North Korea describe Kim as an eloquent and tireless orator, primarily to the military units that form the base of his support.
He also made numerous trips to factories and other sites to offer what North Korea calls "field guidance." As recently as last week, the North's news agency reported on trips to a supermarket and a music and dance center.
"In order to run the center in an effective way, he said, it is important above all to collect a lot of art pieces including Korean music and world famous music," the Korean Central News Agency story read in part.
The world's best glimpse of the man came in 2000, when a liberal South Korean government's conciliatory "sunshine" policy toward the North culminated in the first-ever summit between the two Koreas. A second summit was held in 2007 with then South Korean President Roh Moo-hyun.
Kim was said to have wide interests, including professional basketball, cars and foreign films. He reportedly produced several films, mostly historical epics with an ideological tinge.
A South Korean film director claims Kim had him and his movie star wife kidnapped in the late 1970s, spiriting them to North Korea to make movies for a decade before they managed to escape during a trip to Austria.
Kim rarely traveled abroad and then only by train because of an alleged fear of flying, once heading all the way by luxury rail car to Moscow, indulging in his taste for fine food along the way.
One account of Kim's lavish lifestyle came from Konstantin Pulikovsky, a former Russian presidential envoy who wrote the book "The Orient Express" about Kim's train trip through Russia in July and August 2001.
Pulikovsky, who accompanied the North Korean leader, said Kim's 16-car private train was stocked with crates of French wine. Live lobsters were delivered in advance to stations.
A Japanese cook later claimed he was Kim's personal sushi chef for a decade, writing that Kim had a wine cellar stocked with 10,000 bottles, and that, besides sushi, Kim ate shark's fin soup -- a rare delicacy -- weekly.
"His banquets often started at midnight and lasted until morning. The longest lasted for four days," the chef, who goes by the pseudonym Kenji Fujimoto, was quoted as saying.
Kim is believed to have curbed his indulgent ways in recent years and looked slimmer in more recent video footage aired by North Korea's state-run broadcaster.
Disputing accounts that Kim was "peculiar," former U.S. Secretary of State Madeleine Albright characterized Kim as intelligent and well-informed, saying the two had wide-ranging discussions during her visits to Pyongyang when Bill Clinton was U.S. president. "I found him very much on top of his brief," she said.
Kim's marital status wasn't clear but he is believed to have married once and had at least three other companions. He had at least three sons with two women, as well as a daughter by a third.
His eldest son, Kim Jong Nam, who is about 40, is believed to have fallen out of favor with his father after he was caught trying to enter Japan on a fake passport in 2001 saying he wanted to visit Disney's Tokyo resort.
His two other sons by another woman, Kim Jong Chol and Kim Jong Un, are in their 20s. Their mother reportedly died several years ago.
The Associated Press contributed to this report.