Kim Jong Un's train has arrived in Vietnam for the North Korean leader's second summit with US President Donald Trump.

Vietnamese troops in crisp white uniforms and black boots stood at attention to welcome Kim on a red carpet beneath large North Korean and Vietnamese flags at the Dong Dang railway station on the China-Vietnam border.

A crowd gathered along the road near the station to wave North Korean flags and bouquets of flowers on a cold, drizzling morning.

It wasn't clear if Kim had visited any places in China on his trip from Pyongyang, the North Korean capital, to the border.

Press reports speculate that he will drive the 170km to Hanoi, the Vietnamese capital, ahead of his meeting tomorrow with Trump.