US President Donald Trump said on Thursday that it wasn't a "good time" to strike a denuclearisaton deal after talks with the North Korean leader Kim Jong Un broke down in the Vietnamese capital Hanoi.

After an abrupt end to the summit with North Korea's leader Kim Jong Un, US President Trump said: 'Sometimes you have to walk.'

Trump and Kim cut short their second summit Thursday without reaching an agreement, a stunning collapse of talks that caused both leaders to leave their Vietnam meeting early and cancel a planned signing ceremony.