North Korean state television reports that Supreme Leader Kim Jong Il has died at the age of 69.

An announcer said he died Saturday of physical and mental over-work. Some reports say he died from a heart attack, and was traveling on a train at the time.

Kim Jong Il came to power after his father, North Korea's founder Kim Il Sung, died in 1994. Reliable biographical information about Mr. Kim is scarce. He rarely appeared in public and his voice was seldom broadcast.

He may be best remembered for boosting North Korea's nuclear program, while millions of his countrymen and women were starving.

Late last year, Mr. Kim promoted his youngest son Kim Jong Un to the rank of four-star general, in what was seen as a bid to extend the world's only communist family dynasty to a third generation.

Analysts say it remains to be seen whether there will be a power struggle for leadership among the top generals or whether there will be another smooth generational transfer of power.