Long-time North Korean president Kim Jong Il died on Saturday of a reported heart attack. He was 69.

Kim's death was announced on Monday by state television from Pyongyang, the nation's capital. A North Korean announcer said Kim, known as the supreme leader in the communist nation, died of physical and mental over-work on his way to give field guidance.

We took every emergency measure we could, but the great leader passed away, the North Korean statement said. 

Kim may have had a stroke in August 2008, and was also rumored to have pancreatic cancer, diabetes, and heart disease. He was also believed to be 70, not 69.

After inheriting the presidency upon his father's death in 1994, Kim was frequently at odds with the U.S., particularly after the attacks on Sept. 11. North Korea has had strained relations with the U.S. for several years, though in Oct. 2011, the two nations reportedly narrowed their differences and have increased talks.

Under Kim, North Korea has increased its military spending to roughly a quarter of GNP, and roughly 20 percent of men ages 17-54 are in the regular armed forces. North Korea has long been suspected of being a nuclear-weapons threat.

Known for his eccentric personality and unique tastes, Kim was frequently photographed in jumpsuits, and had a haircut that was intended to provide the allusion that he was taller.

Last year, Kim unveiled his third son, Kim Jong Un, who is in his 20s, to be his successor.