A published report says North Korean leader Kim Jong Il has appointed his second-eldest son to a top post in the ruling party - putting him in line to eventually run the country.

The Japanese newspaper Mainichi Shimbun says Kim Jong Chol has been named a vice director of the Workers Party of Korea. It is the same post that Kim Jong Il was appointed to by his father, the late Kim Il Sung.

The newspaper cites North Korean sources for its report. They suggest that the younger Kim is following "an orthodox course" mirroring his father's rise to take over as head of the world's only communist dynasty.

There is no official confirmation of the Japanese newspaper report, either in North or South Korea.

It has been rumored for years that Kim Jong Il passed over his eldest son, Kim Jong Nam, to designate a successor. The second son, Kim Jong Chol, said to be about 26 years old, is the son of the elder Kim's current and third wife, Ko Yong Hee.

North Korea is one of the most secretive societies. The government there keeps tight control over what information is released to the outside world -- especially when it involves affairs of state.

Some information for this report was provided by AFP and Reuters.