North Korean leader Kim Jong-Il visited the Chinese industrial city of Harbin on Sunday on a surprise trip to China believed linked to his country's succession process, a report said. Kim arrived in the northeastern city at midnight and visited industrial sites and provincial officials there after prolonging his trip, South Korea's Yonhap news agency reported, citing sources in the city. He was expected to leave Harbin -- the capital of Heilongjiang province -- at 10.00pm Sunday (2000 PST) or 6.00am Monday (2300 GMT Sunday), as access to the train station will be restricted during those times, Yonhap said. Kim is believed to have been in China since Thursday, travelling on his private train and possibly accompanied by his son Kim Jong-Un, his apparent successor as leader of the isolated communist state.