“There’s a definite fissure in the alliance. You can see it in Pence’s face if nothing else,” said Van Jackson, a former policy adviser to the US secretary of defence. “The US and South Korea want to present a united front, but they have completely different priorities: South Korea doesn’t want war, and the US doesn’t want North Korea to have nuclear weapons.”

Despite Washington’s hardline approach to dealing with North Korea, Pence made a small concession on Monday, saying the US was willing to talk directly with North Korea in what he called “maximum pressure and engagement at the same time”, according to the Washington Post.

However, if South Korea’s efforts do lead to direct talks between the US and North Korea, those negotiations would be “laughable”, Jackson said.

“One side demands immediate de-nuclearisation and the other says it will never give up its nuclear weapons.”