A U.S. public radio broadcaster says U.S. intelligence authorities are closely watching the health of leaders of autocratic regimes.

The list includes North Korean leader Kim Jong-il, former Cuban President Fidel Castro and Sultan bin Abdul-Aziz, Crown Prince of Saudi Arabia.

National Public Radio said that as the death of a powerful leader in an autocratic state or monarchy could lead to a political crisis, U.S. intelligence is weighing the possible effects on America if any of the three were to die.

The report says the issue is more pressing with Kim Jong-il as Kim, in his early 60s, apparently suffered a stroke last summer and has demonstrated diabetic symptoms.