A North Korean official said in China people talk of Kim Jong Un as if he were his father's successor "but there's been no formal announcement on this in North Korea," the Chosun Ilbo newspaper in Seoul reported Friday.
A North Korean refugee told the newspaper he had never heard the name Kim Jong Un before.
A former soldier who fled North Korea said, "Neither Kim Jong Un nor the succession have ever been mentioned in lectures around military camps."
Kim Jong Il fell ill last year, fueling speculation about his health and the fate of the reclusive communist country's leadership. More recently, North Korea sparked international derision when it conducted an underground nuclear test and test-fired several missiles.
Another defector told Chosun Ilbo, "It's not easy for North Korea to officially designate the heir apparent in the current circumstances."