WASHINGTON - The White House said late Sunday that the United States is in close touch with South Korea and Japan over the death of Kim Jong-il, top leader of the Democratic People's Republic of Korea (DPRK), and remains committed to stability on the Korean Peninsula.

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

"The president has been notified, and we are in close touch with our allies in South Korea and Japan," he added. "We remain committed to stability on the Korean peninsula, and to the freedom and security of our allies."

Kim Jong-il passed away Saturday at the age of 69 "from a great mental and physical strain," the DPRK's official KCNA news agency reported on Monday.

Kim died "from a great mental and physical strain at 08:30 (2330 GMT Friday) December 17, 2011, on a train during a field guidance tour," said the report.

Kim, 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, it added.