Mystery of 'trip to China' by country's aged leader

North Korea's ruler Kim Jong-il made a surprise visit to China yesterday, South Korean media reported, amid confusing reports about the purpose of the trip and the presence of his son.

Media in Seoul quoted South Korean presidential and government sources as saying the 69-year-old leader travelled by train yesterday morning. Earlier, the media outlets reported that it was youngest son and heir apparent Kim Jong-un who arrived in Tumen, in the north-eastern Chinese province of Jilin. A presidential source would not confirm the later reports.

If the elder Mr Kim's visit is confirmed, it would be the North Korean leader's third trip to China in the past 12 months. In the past, such visits have been shrouded in mystery, and it has taken days for China or North Korea to admit a visit was underway.

Kim Jong-il, who travels by train due to a fear of flying, visited China last May and August. In the latter visit, he met Chinese President Hu Jintao in the north-eastern Chinese city of Changchun and said that he was committed to denuclearisation. Yet, in November the North revealed a uranium enrichment programme, opening a second route to make a nuclear bomb along with its plutonium programme.

Kim Jong-il had a suspected stroke in 2008 and analysts had thought his visits last year were to shore up support for a handover of power to his youngest son, Kim Jong-un. But the elder Mr Kim's health appears to have improved significantly, prompting diplomats and analysts to re-evalute their assessment of the succession.

Recently published images of the so-called "Dear Leader" show him portly and pudgy-faced.