UK's Johnson urges North Korea to 'change course' on nukes

In a speech on global security in London, Johnson urged the government of Kim Jong Un to "change course" and engage in diplomacy to resolve the crisis.

"By continuing to develop nuclear capabilities, Kim risks provoking a reaction in the region that is at once defensive and competitive, that reduces not increases his security and therefore reduces not increases the survival chances of the regime," Johnson said.

North Korea has dramatically ramped up its nuclear weapons program, launching intercontinental ballistic missiles that can potentially strike the US mainland and a conducting its largest-ever underground nuclear explosion.

Johnson called for North Korea's neighbor China to lead efforts to pile economic pressure on Pyongyang, but also said US Secretary of State Rex Tillerson had rightly offered North Korea "sensible reassurances" that it does not seek regime change or invasion.

But he said Trump has an "absolute duty to prepare any action" to keep America and its allies safe.

"I don't think anybody can conceivably want a military solution to this problem," Johnson said. "And yet clearly it must remain on the table."

Johnson told a conference organised by the Chatham House international affairs think tank that diplomacy had succeeded in limiting the spread of atomic weapons beyond a handful of countries.