North Korean leader Kim Jong-il has died at the age of 69, state-run television has announced.
Mr Kim, who has led the communist nation since the death of his father in 1994, died on a train while visiting an area outside the capital, the announcement said.
He suffered a stroke in 2008 and was absent from public view for months.
His designated successor is his third son, Kim Jong-un, who is thought to be in his late 20s.
North Korea's state-run news agency, KCNA, urged people to unite behind the younger Kim.
"All party members, military men and the public should faithfully follow the leadership of comrade Kim Jong-un and protect and further strengthen the unified front of the party, military and the public," the news agency said.
State media also referred to him as the "great successor to the revolutionary cause" in what appeared to be the first such reference.
It's hardly surprising, given his poor health in recent years, but it will be interesting to see how (or if) North Korea changes under the rule of his son, if the son can keep power. Time will tell, I guess.