The secretive leader of North Korea, Kim Jong-il, is dead at the age of 69.
A tearful announcer dressed in black appeared on North Korean state television Monday morning and announced Kim Jong Il's death.
She says Kim passed away on Saturday, from what she described as a ?great mental and physical strain.?
The official report says the North Korean leader had a heart attack while on a train during what it called a ?field inspection.? It says every possible measure was taken to save his life, but that an autopsy on Sunday confirmed the cause of death.
Kim is believed to have suffered a stroke in 2008 and has appeared visibly frail in the limited number of photos recently released.
North Korea is a Communist country and has so far maintained a system of hereditary succession. Kim inherited North Korea's leadership from his father Kim Il Sung, who died in 1994. In September 2010, Kim Jong Il named his youngest son Kim Jong Un as his successor.
Peking University international relations professor Zhu Feng calls Kim's death ?surprising.?
?North Korea is not just some sort of failed state, but North Korea is also a dangerous state because it has the nuclear weapon," said Zhu. "So, then the sudden passing away of their top leader will certainly produce great worry, uncertainty and even instability.
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Shortly after the announcement of Kim?s death, South Korea put its military on ?high alert? and President Lee Myung-bak convened his national security council.
The White House said President Barack Obama had been notified and U.S. officials are in touch with their South Korean and Japanese counterparts.
China and North Korea have traditionally described their friendship as being as close as ?lips and teeth.? But Zhu says Chinese leaders had mixed feelings about Kim Jong il.
"On the one hand of course, he is a strong man and he continued to just rule his country. But on the other hand, we also see on his rule [although] North Korea's economy was calm, North Korea's international behavior was provocative,? he said.
Zhu says Chinese leaders were most concerned with Kim's nuclear ambitions.
North Korea has announced that the official funeral for Kim will be held on December 28. Heir apparent Kim Jong-un has been named as the head of the funeral committee.