US President Donald Trump has landed in Hanoi ahead of his second nuclear summit with North Korean leader Kim Jong Un.

Mr Trump arrived late Tuesday in Air Force One after a long flight that included refueling stops in Suffolk and Qatar.

He waved from the stairs of the presidential plane, then shook hands with dignitaries and walked along a red carpet to his motorcade.

Trump meets officials as he arrives in Hanoi on Tuesday evening. Credit: AP

Mr Kim had arrived in Vietnam's capital in an armoured limousine earlier on Tuesday after a 70-hour train journey that started in Pyongyang and wound through China to a Vietnamese border town.

A crowd gathered along the road near the station to wave North Korean flags and bouquets of flowers as Mr Kim stepped into a black limousine that was then surrounded by bodyguards who ran alongside their leader as he left the station.

The two leaders are slated to meet over two days, first at dinner on Wednesday followed by meetings on Thursday.

North Korean leader Kim Jong Un is welcomed upon arrival in Dong Dang Credit: Minh Hoang/AP

Mr Kim’s arrival comes as Vietnamese officials scramble to finish preparations for a rushed summit that is meant to deal with one of Asia’s biggest security challenges: North Korea’s pursuit of a nuclear programme that stands on the verge of viably threatening any target on the planet.

Although many experts are sceptical Mr Kim will give up the nuclear weapons he likely sees as his best guarantee of continued rule, there was a palpable, carnival-like excitement among many in Hanoi as the final preparations were made for the meeting.

Officials in Hanoi said they only had about 10 days to prepare for the summit — much less than the nearly two months Singapore had before the first Trump-Kim meeting last year – but still vowed to provide airtight security for the two leaders.

“Security will be at the maximum level,” Vietnamese deputy minister of foreign affairs Le Hoai Trung told reporters.

The ultra-tight security will be appreciated by North Korean authorities, who are extremely vigilant about the safety of Mr Kim, the third member of his family to rule the North with absolute power.

Mr Kim was filmed having a cigarette break at train station en route to Hanoi. Credit: TBS/JNN

Roads on Tuesday were shut down from the border with China all the way to Hanoi, 106 miles away.

“I really hope to catch a glimpse of Kim Jong Un. He is an interesting man. And he rarely travels anywhere so it would be great to see him here,” said Nguyen Trong Toan, a retired teacher who was waiting by the side of the street on Mr Kim’s expected travel route.

There are high expectations for the Hanoi summit after a vague declaration at the first meeting in June in Singapore that disappointed many.

Kim Jong Un waves from a car ahead of his second summit with Donald Trump Credit: Minh Hoang/AP

In a meeting with senior aides in Seoul, South Korean president Moon Jae-in said that the Trump-Kim talks would be a critical opportunity to achieve peace on the Korean Peninsula.

Mr Moon, who met Mr Kim three times last year and has lobbied hard to revive nuclear diplomacy between the US and North Korea, is eager for a breakthrough that would allow him to push ambitious plans for inter-Korean engagement, including lucrative joint economic projects that are held back by US-led sanctions against the North.

“If President Trump succeeds in dissolving the world’s last remaining Cold War rivalry, it will become yet another great feat that will be indelibly recorded in world history,” Mr Moon said.

Mr Trump, via Twitter, has worked to temper those expectations, predicting before leaving for Hanoi a “continuation of the progress” made in Singapore but adding a tantalising nod to “Denuclearisation?”

He also said that Mr Kim knows that “without nuclear weapons, his country could fast become one of the great economic powers anywhere in the World”.