North Korean Leader Kim Jong Il, 69, Has Died

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.

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. 

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.

The Associated Press contributed to this report.