Washington, Dec 19 (IANS): The US is in close touch with South Korea and Japan over the death of North Korea's top leader Kim Jong-il, and remains committed to stability in the Korean peninsula, said the White House.

Kim died Saturday at the age of 69 "from a great mental and physical strain", North Korea's official KCNA news agency revealed Monday.

"We are closely monitoring reports that Kim Jong-il is dead," White House spokesperson Jay Carney said in a statement.

"The president (Barack Obama) has been notified, and we are in close touch with our allies in South Korea and Japan," Xinhua quoted him as saying.

"We remain committed to stability on the Korean peninsula, and to the freedom and security of our allies."

Kim died Dec 17 on a train during "a field guidance tour". The North Korean leader, who had received medical treatment for his cardiac and cerebrovascular diseases for a long period, suffered "an advanced acute myocardial infarction, complicated with a serious heart shock" on the train, the official report said.