North Korean leader Kim Jong-Il was reportedly heading to Beijing on Tuesday for talks likely to centre on desperately needed aid for his sanctions-hit regime and stalled nuclear dialogue. Kim's first trip in four years to China -- North Korea's sole major ally and its main source of finance, food and fuel -- has been seen by some analysts as a sign that talks on ending the North's atomic weapons drive could soon resume. But others say mystery over the sinking of a South Korean warship in March -- an incident in which 46 sailors were killed, and which Seoul has hinted could be Pyongyang's fault -- clouds any hope for an early return to dialogue. Kim on Tuesday inspected a port under construction outside the northeastern city of Dalian, where he spent the night after arriving in China, South Korea's Yonhap news agency reported, citing unidentified sources in the city. The North Korean leader's special armoured train was in the Dalian rail station, the sources said, prompting speculation that he would soon head to the capital Beijing -- a journey of 8-10 hours, depending on the route. The reclusive Kim was expected to meet Chinese President Hu Jintao on Wednesday, before heading home Thursday, Yonhap reported. There has so far been no formal confirmation of Kim's trip from either the Chinese or the North Korean side. Chinese foreign ministry spokeswoman Jiang Yu told reporters she had no information on the issue, although she spoke about the long "tradition of high-level exchanges and visits" between the neighbours. Tourism officials on the border told AFP on Monday that the 68-year-old Kim -- who reportedly suffered a stroke in mid-2008 -- had arrived in China. Kim, who is said to dislike air travel, has visited China four times since 2000, each time by train. The last trip, in January 2006, was also shrouded in secrecy and only formally announced after it had ended. Analysts have said China could use the current trip to press Kim to return to the six-party nuclear disarmament talks he quit in April last year, in return for badly needed aid. North Korea has suffered persistent food shortages since the Soviet Union collapsed two decades ago. The shortages were aggravated last November by a bungled currency reform. North Korea had agreed in previous rounds of the nuclear dialogue -- which groups the two Koreas, China, Russia, the United States and Japan -- to end its weapons drive in return for security guarantees and fuel aid. But it angrily quit the talks in April last year and carried out its second atomic weapons test the following month. Pyongyang says it will not go back to the nuclear dialogue until UN sanctions are lifted, and until the United States commits to holding talks on a formal peace treaty. But US and South Korean officials argue the talks cannot restart until suspicion is resolved about any North Korean involvement in the March 26 sinking of the Cheonan warship, which was ripped apart by an external blast. South Korean President Lee Myung-Bak said Tuesday that his instinct told him the incident was "involving inter-Korean relations" -- the closest he has yet come to blaming the North. Pyongyang has angrily denied all responsibility. Seoul on Tuesday urged China to play a "responsible role" in resolving tensions on the Korean peninsula sparked by both the sinking of the Cheonan and problems with an inter-Korean tourism project. Yonhap, quoting a foreign ministry official in Seoul, said South Korea was "not happy" about the timing of Kim's trip, with the warship probe ongoing.