Kim's death was made public on Monday, with officials indicating that he actually died two days earlier while riding a train.
Reuters notes that the country had begun transferring power to his son, Kim Jong-un, who is believed to be in his late 20s.
The Korean Central News Agency, North Korea's state news agency, issued several statements on Monday. A release titled "Kim Jong Il Passes Away (Urgent)" said that he "passed away from great mental and physical strain" at 8:30 a.m. on Saturday, Dec. 17. A separate article entitled "Medical Analysis of Kim Jong Il's demise" added that Kim suffered an "advanced acute myocardial infarction, complicated with a serious heart shock."
Kim reportedly suffered a stroke in 2008, but appeared relatively healthy on recent trips around Asia, which were documented by state media.
The White House released a statement late Sunday evening in Washington.
