China's official Xinhua News Agency issued a almost identical report, while Beijing's North Railway Station was cocooned in security, with dozens of police and paramilitary troops patrolling outside.
Dozens of security vehicles and officials blocked the roads around a train station in the Chinese border city of Dandong through which the train passed, according to Yonhap.
The train had been due to arrive in Beijing around 10 a.m. Tuesday.
It can not be ruled out that Kim and Xi will discuss shipping the North's intercontinental ballistic missile out of the country to dismantle them, an issue that the U.S. wanted to address, he added.
Last year, Kim travelled to China three times to meet with Xi before and after summits with US President Donald Trump and South Korean President Moon Jae-in.
Mr Jo Song Gil, the 44-year-old who was until recently North Korea's acting ambassador to Italy, disappeared with his wife after leaving the embassy without notice in early November, South Korean lawmakers said last Thursday. After resettling in South Korea in 1997, Hwang became a vocal critic of the North Korean leadership he had a hand in building, which led to threats and attempts on his life Seoul blamed on Pyongyang.
After years of cool relations following Kim's assumption of power 2011, ties have improved remarkably over the past year as Xi seeks to maintain his influence in the region.
"It will be announced probably in the not too distant future".
Trump earlier said that the U.S. and North Korea are in talks over where to hold their second summit, adding that the decision on the venue will be announced in the "not-too-distant future".
Cheong Seong-chang, a researcher at the Sejong Institute in Seoul, said Kim's summit with Xi was expected to focus on denuclearisation of the Korean peninsula, the establishment of a peace regime to replace the current armistice and relief of sanctions against the North.
He added that Kim would "certainly call on Xi Jinping to give North Korea more economic assistance".
The relationship between the North Korean dictator and the US President has been unprecedentedly friendly in recent months. "The three summits with Xi Jinping in 2018 seem to have made Kim Jong Un very optimistic".
Kim could be looking to leverage his relationship with Xi, who Trump has accused of relaxing pressure on North Korea, to push the U.S.to make concessions in nuclear talks.