Donald Trump praised Kim Jong-un as a “great leader” on Wednesday and talked up North Korea’s “unlimited” economic potential as the pair begun their two-day summit in Vietnam.

The US and North Korean leaders shared a 10-second handshake, warm words and a laugh while posing for the camera as they met for only the second time in Hanoi, the Vietnam capital.

They talked alone at first, save only for interpreters, before enjoying a wider dinner with key members of their administrations at a luxury colonial-era hotel in the city.

Mr Trump, who earlier in the day had tweeted about “my friend Kim”, talked up North Korea’s economic prospects - the carrot with which he hopes to convince Kim to give up his nuclear weapons.

“I think that your country has tremendous economic potential - unbelievable, unlimited," the US president told Kim at the beginning of their one-on-one chat.

"I think that you will have a tremendous future with your country - a great leader - and I look forward to watching it happen and helping it to happen."