The Japanese news agency cited a diplomatic source as saying Kim Chang-son, chief secretary of the Secretariat of the State Affairs Commission of North Korea, had gone to a train station in an unnamed Vietnamese city bordering China Sunday for inspections and security checks.
This has led to speculation that Kim Jong-un could use a train to travel to Hanoi for the second summit between the United States and North Korea on February 27 and 28, Kyodo said.
Kim Jong-un boarded a Boeing 747 from Air China to Singapore for the first U.S.-North Korea summit last year. But when he visited China the same year, he used his own specialized steel-plated train instead.
If Kim Jong-un does in fact board a train to Hanoi, it would take him approximately three days to traverse the 4,023 kilometers from North Korea through China to Vietnam. Security is also a matter of concern as China would need to make sure the train has safe passage through the country before reaching Vietnam.
Kim Jong-un's train is not only steel-plated, but also equipped with conference rooms, bedrooms, satellite phones and televisions.
After getting to Vietnam, Kim Jong-un could visit key industrial sites and meet with Vietnamese President and Party chief Nguyen Phu Trong, South Korean television network MBC reported, citing an unnamed source.
As of Saturday, both U.S. and North Korean delegations had landed in Hanoi to discuss the summit's logistics.
The second Trump-Kim summit will take place in Hanoi on February 27 and 28.
Vietnam has expressed its happiness at hosting the event, as well as confidence that it can host the meeting successfully.
City authorities have said they will patrol certain strategic areas 24/7, including the Noi Bai International Airport, train and bus stations, cultural monuments and electric grids, to ensure security before and during the event.
The first summit was held in Singapore in June 2018, but negotiations failed to make much headway owing to disagreements on the concept of denuclearization.
Both sides are hoping to make further headway at the upcoming summit in Hanoi.