North Korean leader Kim Jong-il may die within three years, according to a senior US envoy.

Kurt Campbell, the assistant US Secretary of State, told ambassador Kathleen Stephens, a South Korean politician and activists in a closed-door session that he doubted the 68-year-old leader would live beyond 2013, South Korea's Chosun Ilbo newspaper said.

Mr Campbell based his estimate on medical information, the report said, citing unidentified sources.

The estimate comes after a state-run South Korean think tank, the Korea Institute for National Unification, said in a January report that Kim Jong Il probably wouldn't survive past 2012. It cited no specific evidence for the estimate.

The report comes amid speculation that the autocratic leader is preparing to hand power over to one of his sons.