North Korean leader rides train on way to Vietnam By Poornima

North Korean leader Kim Jong Un's armoured train chugged across China on Sunday as he headed to his highly anticipated second summit with US President Donald Trump in Vietnam.

Emulating his late father and grandfather, who took epic train trips when they were leaders, Kim set off on the long journey from Pyongyang railway station on Saturday, with a military honour guard seeing him off.

His departure was confirmed by the North's official KCNA news agency, with images showing citizens cheering him as he waved from the train before what could be a 60-hour journey to Vietnam.

The train crossed the border city of Dandong later that day, according to South Korea's Yonhap news agency and the specialist outlet NK News, but its route remained a tightly-held secret.

The train's crossing into China follows days of speculation over Kim's travel plans, as his team gathered in Hanoi ahead of the talks expected next Wednesday and Thursday.

Accompanying the North Korean leader was right-hand man and top general Kim Yong Chol, who met with Trump at the White House last month, his sister and close aide Kim Yo Jong, and other high-ranking officials, KCNA said.

Security was tight before the train's arrival in Dandong, with police cordoning off the border bridge area with tape and metal barriers, and leading an AFP journalist out of the area.

A hotel facing the bridge was closed for impromptu renovations on Saturday.

"The train is long and crossed the bridge slower than the tourist train, but it's definitely him, there's a lot of police presence," an unidentified source told NK News.

Windows on the train were blacked out, the source said, with only headlights turned on as it crossed.

The train usually takes 13 hours to reach Beijing, but there were no signs of heightened security around the railway station on Sunday, indicating the train likely bypassed the Chinese capital on the nearly 4,000-kilometre journey to Vietnam.

Kim has met Chinese President Xi Jinping four times in the past year, briefing his country's sole major ally before and after his historic summits with Trump and South Korean President Moon Jae-in.

Kim, who last met Xi in January, could be saving their next meeting for his return trip to debrief the Chinese leader.

Trump and Kim met in June in Singapore, producing a vaguely worded agreement on denuclearisation, but progress has since stalled, with the two sides disagreeing over what the agreement meant.

Observers say tangible progress is needed in Hanoi to avoid the talks being dismissed as a publicity stunt.

Several sources said Kim was expected to arrive in Vietnam by train, stopping at the Dong Dang station near the China border, then driving to Hanoi.

Soldiers were deployed to Dong Dang station and along the road to the capital, according to AFP reporters at the scene.

Vietnam previously announced the unprecedented move of closing that 170-kilometre stretch of road on Tuesday between 6:00 am and 2:00 pm -- suggesting Kim could travel along it between those hours.

An AFP reporter on Sunday saw Vietnamese military personnel sweeping for mines along the road.

"Vietnam wants to contribute its part to world peace... at this upcoming summit. Vietnam will ensure maximum security and safety to all the distinguished guests to Vietnam," Vietnamese Prime Minister Xuan Phuc told reporters on Sunday.

As Kim travelled, delegations prepared for the summit, with Pyongyang's special representative for the US, Kim Hyok Chol, appearing at a Hanoi hotel on Sunday afternoon for talks with his US counterpart Stephen Biegun, Yonhap reported.

A North Korean cargo plane landed in Hanoi earlier Sunday, carrying members of the Pyongyang delegation, photographs in the Vietnamese press showed.

Rail travel is a family tradition that was started by Kim's grandfather, the North's founder Kim Il Sung, who travelled to Eastern Europe for his longest train ride in 1984.

His late father, Kim Jong Il, travelled all the way to Moscow by train in 2001.

"It sends a strong message to North Koreans that Kim Jong Un has inherited his grandfather's good qualities, and the Kim Dynasty is stronger than ever," said Koh Yu-hwan, professor at Seoul's Dongguk University. Jeong Young-tae of the Institute of North Korean Studies in Seoul said the safest way to travel would be to take a plane provided by Beijing, as Kim did for the Singapore summit.

"But by choosing to travel by their own special train over a Chinese aircraft, Pyongyang may be signalling its willingness to be independent," Jeong said.

The journey from China's frozen northern border to subtropical Vietnam presents a logistical headache and complex security challenges.

Zhao Jian, who studies China's railway system at Beijing Jiaotong University, said one route would take Kim straight down to southern China, before heading west into Guangxi province, which borders Vietnam.

Justin Hastings, associate professor in international relations at the University of Sydney, said that would be "a pretty major operation."