North Korean leader Kim Jong-il's heir apparent, Kim Jong-un, arrived in China by train yesterday on his first visit since being promoted last year. The trip is aimed at garnering Beijing's formal support for the reclusive regime's power succession. Late reports suggested his father had also crossed the border, contradicting earlier reports. Diplomats could only confirm the younger Kim's visit, even though South Korean news quoted South Korean presidential and government sources as saying the 69-year-old leader had also entered China by train in the morning. Diplomats said the young leader, in his late 20s, is likely to meet his mainland counterpart Xi Jinping , who is vice-president and heir-apparent to President Hu Jintao . 'Such a meeting is very likely as it is rational in diplomatic courtesy and necessary in practice for preparing both future leaders to carry on the traditional relationship,' said a South Korean diplomat. Liu Ming, director of the Shanghai Academy of Social Sciences' Korean Peninsula Research Centre, said: 'The visit symbolises China's formal acceptance and support of North Korean power transition.' Liu cited the fact that the trip marks the younger Kim's first visit to the mainland since he was named vice-chairman of the Central Military Commission of the ruling Workers' Party in September. Liu said the visit was an effort to dispel outside doubts about the hereditary succession. Citing a source in the border city of Tumen, Jilin, the South Korean news agency Yonhapsaid the junior Kim was heading to Mudanjiang in Heilongjiang province early yesterday. The route indicated that the leader-in-waiting could tour the areas on the mainland his father visited in August last year. Meanwhile, a mainland diplomat said the junior Kim was likely to visit joint-venture projects in the border area. A construction project aimed at developing a small island in the lower reaches of the Tumen River and the construction of roads connecting bordering cities in both countries would start soon, the diplomat said. The diplomat said the junior Kim was appointed by his father to oversee such projects, seeing them as an experiment of North Korean's openness and market-oriented reform. Kim Jong-un is also expected to visit Harbin, Heilongjiang, as well as Changchun, Jilin - home to a middle school that North Korean founder Kim Il-sung, his grandfather, attended as a teenager.