DONG DANG (Vietnam) • The train station on the Vietnam-China border where Mr Kim Jong Un is expected to arrive by rail was closed to the public and surrounded by armed guards yesterday, days ahead of the North Korean leader's summit with United States President Donald Trump.

Mr Kim boarded his trademark olive-green train in Pyongyang last Saturday, and its armoured carriages were later spotted crossing a bridge into China, although it reportedly bypassed Beijing.

South Korea's Yonhap news agency said the train passed through the Chinese city of Hengyang at about 3.30pm yesterday. Sources in Vietnam said Mr Kim was expected to arrive at the Dong Dang border station in the early hours today following his epic 4,000km, 21/2-day journey.

In an unprecedented move, the entire 170km stretch of road from Dong Dang to Hanoi will be completely closed from 6am to 2pm today for Mr Kim's motorcade.

An Agence France-Presse reporter at the scene saw armed guards stationed at Dong Dang station yesterday morning, while workers tended to the rail tracks.

"(The station) is closed, no public access. We don't know when it is closed until but around tomorrow," a guard told Agence France-Presse, requesting anonymity.

Mr Kim's route through China has remained a tightly guarded secret.

Ifeng, the online Chinese-language news website of Hong Kong-based Phoenix Television, posted a video on its Twitter-like Weibo account showing what it described as Mr Kim's special train passing through Wuhan in the central province of Hubei at 7.15am yesterday.

Vietnam has been hastily preparing for the second meeting between Mr Kim and Mr Trump after their historic first summit in Singapore in June last year.

It said last Saturday that Mr Kim would make an official visit to the country "in the coming days", but did not say whether that would be before or after the summit, which begins tomorrow and ends on Thursday.

Two sources told Agence France-Presse that Mr Kim would stay at a modern hotel in downtown Hanoi, about 1km from the colonial-era Government Guesthouse where the summit could take place.

The Melia Hanoi Hotel boasts gorgeous views of the city and is connected to Hanoi's only Rolls-Royce dealership catering to the city's growing class of super-rich.

The White House press centre will be set up at the same hotel, and North Korean security staff were seen entering the building on Sunday.

AGENCE FRANCE-PRESSE, REUTERS